If you missed a second of this championship battle, Ravi Ubha provided instant analysis through the duration of the match.
As expected, Williams is doing all the dictating. You get the feeling this could be a rapid second set, much shorter than the first.
Jankovic is now trying to become the second woman in the last 18 Open finals to win after dropping the first set. Arantxa Sanchez-Vicario did it against Steffi Graf in 1994. By the way, 1995 was the last time a women's final in New York went the distance.
Williams picks up where she left off and holds to love. 1-0.
Now at 0-15 and Williams has won 11 of the last 13 points. Williams is threatening to dominate, moving to 15-40. Jankovic needs to hold to realistically stay in this one, and holds on to get to game point.
Williams pulls it back to deuce, but Jankovic comes out a winner on the next point, uncorking a backhand down the line. "I love you Jelena," a fan yells.
It does little good. We're back to deuce, No. 3. Jankovic holds, and that's a big save. 1-1, and Jankovic still in this one.
"The longer the rally the better chance she's got," McEnroe says after Jankovic takes a 15-0 lead on Williams's serve. At 15-all, perhaps the point of the match. Williams is pulled out wide with a forehand, and replies with a cross-court forehand herself. Jankovic delivers a drop shot, Williams gets to it, and later dispatches a volley.
Another longer rally, and Jankovic prevails again. Still game point for Williams at 40-30. A few Serb fans, wearing red wigs, chant, "Jelena, Jelena." Williams frames a forehand volley but it gets the job done for 2-1.
"She's making a match of this," Carillo says of Jankovic, and the crowd is appreciative.
Jankovic is the beneficiary of a net court this time, on a swinging volley. Williams chases it down, but Jankovic has the whole court to reply and issues a perfect lob for 30-15. The fans enjoy that one, and so does Jankovic -- she watches it on the big screen.
At 30-all, a forehand down the line by Jankovic gives her game point, though a backhand into the net brings it to deuce. A backhand down the line is just long by Williams, and it's 2-2.
A third double fault for Williams, cheered by a few, gives Jankovic an opening, and there's more of an opportunity following a backhand long. Jankovic has to take her chances, and missing well wide on a second serve, on her backhand, won't help. 15-30.
Did we mention how nice it is to have a big serve? A service winner, ace and service winner make it 3-2 for Williams in a flash.
How long can Jankovic continue to hang on?
Williams is only serving at 47 percent in the second set, yet has won 86 percent of those points. In the first, the numbers were, bizarrely, 67 and 55, respectively.
Jankovic obviously needs to play outside her comfort zone, and she attempts a running forehand down the line. She misses and it's 15-all. At 15-30, Williams comes in and forces an errant forehand pass into the net.
A third and fourth break point for Williams.
The first is saved, and a second goes by on a forehand long.
Could Serena be tightening up with the finish line in sight?
Maybe, as another error makes it advantage Jankovic. Deuce again, a cross-court winner. A good save by Jankovic, and she holds for 3-3 on a miscued return.
Williams changes rackets, which appears to irk Jankovic, who has words with the chair umpire. Williams hasn't been threatened on serve this set, and goes up 40-15 on a net approach -- she's now 16 for 21 at net.
A strange point next, when a linesperson is unsighted on a looping cross-court Jankovic stroke. Williams thinks it's out, and the chair umpire, Alison Lang, orders a challenge -- apparently that's within the rules. The ball is in, and the point is replayed.
"The chair has two challenges left this set," McEnroe pipes.
That could be a turning point. Jankovic seizes the momentum and breaks when a Williams drop shot goes into the net. 4-3 Jankovic.
Jankovic is having a good time, smiling as she looks at the big screen on the changeover. Williams is unravelling, losing seven of the last eight points to fall behind 30-0. A third set beckons.
Hold the phone. We're back at 30-all, Williams unleashing a cross-court forehand winner. A service winner, however, makes it game point. Jankovic needs this hold -- and she does. 5-3.
Williams nets a forehand into the highest part of the net.
"The crowd just loving what Jankovic is giving off," McEnroe said.
Revenge for Jankovic to start the ninth game. With Williams at the net, Jankovic back pedals and uncorks a smash straight at Williams, who gets a racket to it. The ball, as expected, floats out.
Jankovic has three set points at 0-40.
The first two are saved, and on the third, Jankovic is forced into a backhand mistake. Deuce. A service winner makes it advantage Williams -- a 35th winner, compared to 35 unforced errors. Jankovic is at 13 and16, respectively.
A missed return gives Williams the game, holding for 4-5. What a chance missed for Jankovic.
The roller coaster ride continues.
Somewhat predictably, Williams takes a 30-0 lead on an overhead and double fault. A sizzling winner into the corner, and it's eight straight points.
Is it Jankovic's time to rally? Yes.
She claims three straight points, punctuated by a missed return on a second serve that's under 80 mph. Williams is now 0-for-7 on break points this set. She gets an eighth chance, by forcing Jankovic into an error on an exhausting point.
Missed again, a backhand into the net the culprit.
Another chance goes astray when a Jankovic forehand gives Williams little chance on a pass.
Can you believe that? An ace out wide, and it's a fourth set point. Jankovic is actually out-acing Williams 3-2.
Guess what's next? A double. Deuce again, No. 4.
Break point for Serena, when the umpire calls a double bounce seconds before Jankovic delivers a deft backhand winner. The right call, and break point once more.
Finally the break, and it's 5-5. Jankovic did well to stay in the rally with a couple of forehand saves, but a forehand pass is too much. Great drama.
Williams has to capitalize on the momentum shift.
Jankovic, though, is hanging in there. At 30-15, a 24-stroke rally ends with Jankovic pummelling Williams into an error.
What a great point, drawing a standing ovation, and what a missed chance by Jankovic. Williams chases down a net cord, and a short reply ensues. With the whole court open, Jankovic doesn't do enough with a lob, and Serena eventually wins the point. 40-30.
Not good by Jankovic. She complains the umpire again about Williams taking too long between points, drawing a few boos. Not another Serb upsetting the crowd.
This is turning into quite a match. Williams makes a stab drop volley, then turns to the crowd and celebrates. One game away from a ninth Grand Slam title at 6-5.
Jankovic wins the first point for 15-0, but Williams shows her athleticism on the next by staying in a rally, coming in and drawing an error. We're past two hours and Williams is two points away from victory at 30-30, putting away a smash.
Match point now, as Williams lets loose on a cross-court backhand, forcing a backhand error.
It's saved. Jankovic shows no fear, going for a forehand down the line. Williams gets a racket to it but not much more.
Jankovic claws back to game point, only to serve a double, her fourth. Costly again, as on the next point, a backhand goes into the net. Match point No. 2.
There it is. Game, set, match. Williams finishes it with an angled backhand winner. 6-4, 7-5.
She tosses her racket in the air and proceeds to bob up and down like a kangaroo. She exchanges a hug with Jankovic at the net, and says, "I'm sorry, I'm so excited." Williams also gets an embrace from dad, Richard.
A third U.S. Open title for Williams, and she's back at No. 1, to boot.
Serena Williams wins the match and title 6-4, 7-5.
Williams becomes the second straight woman, following Justine Henin, to win the Open without dropping a set.
Jankovic has only herself to blame for not taking proceedings to a third set, at the very least. She'll look back at the fourth game of the first, and the four missed set points in the second with much dread.
She's clearly disappointed, but Jankovic, a drama queen, steals the show in the awards ceremony. She grabs the microphone from emcee Carillo, wanting to thank her entire entourage and various others, including drivers.
Later, when Williams is awarded her winner's check of $1.5 million -- she now moves to No. 3 on the all-time women's prize money list -- Jankovic, too busy talking before, utters, "How much did I get?'' (It's $750,000, for those wondering.)
Williams won't mind that she was upstaged when it ended. She got what she wanted.
John McEnroe and Mary Carillo, calling the match for CBS, aren't giving Jankovic much chance. "I think this occasion might be too much," for the world No. 2, McEnroe says, after extolling her defensive virtues.
Anita Baker gets everyone in the mood by delivering a rousing edition of "America the Beautiful," and icon Billie Jean King performs the coin toss. Jankovic, clad in yellow yet again, calls tails and wins it, electing to receive.
Jankovic, walking to the baseline to receive, lets out a little smile. Bouncing up and down, the smile remains. Williams, in red, waits before trotting to the baseline.
And we're off.
Williams delivers a first serve, the return is short, and Williams thumps a backhand cross-court winner. Her earring falls off, such is the power with which it's struck. A stunning backhand winner by Jankovic makes it 15-15.
Williams has the biggest serve in the women's game and unleashes a good first delivery to set up the point and go up 30-15.
Up 40-15, we're back to deuce with the first two Williams unforced errors. Deuce No. 2 when Williams nets a backhand; another long rally won by Jankovic, who doesn't appear to be nervous. Deuce No. 3 thanks to an errant Williams forehand.
So far, as expected, Williams doing the dictating, good or bad.
A service winner, followed by a backhand winner, finally gives Williams the game. 1-0 Williams.
Jankovic to serve, not one of her strengths. It lacks punch, and she's also third in the tournament in double faults. If Williams is on her return game, look out.
But a good start. Jankovic takes a 40-15 and holds at 30 when Williams pushes a forehand volley long. 1-1. At this point, six winners and five unforced errors for Williams. Jankovic is one and one.
Williams now even when a groundstroke sails long. An opening here for Jankovic, who takes a 30-0 lead on a double fault. Make that three break points when a backhand sails long. Jankovic does well to return a fierce Williams serve back, it floats in, and another unforced error, into the net, ensues. 2-1 Jankovic, up a break.
Jankovic is on a roll, thanks mostly to her opponent, though a backhand down the line makes it 15-0. Two returns long make it 40-0, and she's won eight consecutive points. Williams stems the tide with a forehand down the line.
Jankovic misses with a backhand wide and here's a pivotal point. You figure Jankovic needs to consolidate the break, but no, we're at deuce when an attempted forehand down the line can't clear the net.
Advantage Williams when she works Jankovic around the court and finishes things off with a thundering swinging volley cross court. The first break point for Williams, who duly converts when a Jankovic backhand, her steadiest stroke, goes long. 2-2.
How big could that be?
Jankovic at her defensive best on the next point, but it's still not good enough. Jankovic is doing sprints on the baseline, thoroughly getting moved around. She sees the funny side, though, and lets out a smile -- during the point.
Williams has now won eight points in a row to lead 30-0. She holds at 15 and wrestles back the lead when a backhand goes into the net. Serena leads 3-2.
Just a reminder of what happened in the final of the Sony Ericsson Open in Miami this spring. In the final, Williams led 6-1, 3-0 before Jankovic forced a third set. A Williams surge might be on the way here.
Williams is a great athlete, and shows it by chasing a drop shot and later following it up by putting away a volley. 0-15. Level at 15-all thanks to a forehand winner down the line.
Virgin boss Richard Branson and Jennifer Capriati, the three-time Grand Slam champion battling shoulder and wrist injuries, are among those in the crowd.
What they see next is a Jankovic double fault to fall behind 30-40. She makes the first challenge, and video confirms the ball was well long. Williams now leads 4-2 following a forehand into the corner. That fourth game is looking huge.
Williams makes her first challenge, on a cross-court forehand, and the call stands, the ball less than an inch wide. At 0-30, Jankovic with an opening, a backhand down the line goes long. Make that 30-all with an ace, her first.
A service winner, clocked at 120 mph, and a volley winner, set up by a good first serve, again, makes it 5-2.
Williams clubbed Russian Dinara Safina in the semifinals, and does the same to Jankovic to open the eighth game. Jankovic does well to chase a drop shot, and a lame duck at the net, Williams drills a forehand straight at her midsection. She instinctively sticks her racket out and steers a winner into the corner.
Jankovic hits an ace, rare for her, and takes a 40-15 lead, only to fall back to deuce. Williams takes advantage of a short ball and pummels an inside-out forehand into the corner. Wow, another race for Jankovic, and in the same game. Williams unsuccessfully challenges.
Jankovic holds to deuce, and it's 5-3. Williams now serving for the set. Let's see if any nerves surface.
No nerves on the first point, just a good, deep return that forces a forehand into the net. 0-15. The collar is tightening. 0-30 on a double fault. Jankovic delivers a gorgeous backhand pass for 0-40. The up-and-down match continues.
A Williams winner and Jankovic forehand miss pulls it back to 30-40. And there's the break. A Williams backhand slice goes into the net, and Jankovic pumps her fist. 5-4 Williams, on serve.
Comedian Will Ferrell, in the stands to watch Andy Murray's semifinal win over Rafael Nadal earlier today, is back for the women's final. Jankovic ain't smiling.
The first point goes to Williams thanks to lucky net cord, and a forehand angled winner makes it 0-30. Now 0-40, three set points.
What did we say about Jankovic's serve?
The first saved when Williams is forced into an error, and a forehand sails long to give Williams the opening set 6-4. Jankovic challenges, more in hope, wrong once again.
Williams with 19 winners and 16 unforced errors in a 47-minute opener.
Williams wins the first set 6-4.
Which Serena Williams shows up for this evening's U.S. Open final? The one who battled past sister Venus in a quarterfinal nail-biter and thrashed the surging Dinara Safina in the semis, or the one who made an overflow of errors in an upset third-round loss to Slovenian Katarina Srebotnik at the French Open?
If it's the former, Jelena Jankovic's first Grand Slam final figures to be memorable for all the wrong reasons, with Williams' huge serve, punishing groundstrokes and athleticism bound to overwhelm the elastic Serb.
Jankovic is, however, resilient and finally healthy. She'll get her fair share of balls back in play, forcing Williams to make that extra shot. The two have also split their six head-to-heads, all on outdoor hard courts, going 1-1 this season.
Williams' execution is what to watch.
There's plenty at stake besides Jankovic chasing a first and much awaited major: The winner becomes the new No. 1 in the wacky WTA rankings. Williams would return following a five-year gap, the longest in women's history.
Oh, no threat of Tropical Storm Hanna or its remnants, either. Clear skies and temperatures of 78 degrees make for ideal conditions. Enjoy.
Let's hope for a good one.
Ravi Ubha is a frequent contributor to ESPN.com.