PARIS -- So here it is, the first big match of the French Open this year: Novak Djokovic versus Juan Martin del Potro, the third-round meeting circled on draw sheets at the beginning of the week -- the first real threat to the Djokovic phenomenon now known simply as "the streak."
"Beautiful match," said del Potro. "For fight, for play, and hopefully -- for take chance to win."
Formally, it is No. 2 versus No. 26, but much more in reality. Djokovic has without a doubt been this season's No. 1 -- reciting the numbers has become rote by this point. He is unbeaten in 39 matches so far this year, 41 in a row overall. That has put him on the cusp of two records: John McEnroe's 42-0 start in 1984 and Guillermo Vilas' 46 straight match wins.
And it is this tournament that will determine whether he breaks those marks. Djokovic will pass McEnroe if he reaches the semifinals, and Vilas if he wins the title. It would also give him, at long last, the No. 1 ranking, ending the six-year duopoly of Roger Federer and Rafael Nadal.
Oh, and there would be the win in Paris itself -- a third Grand Slam title, and the first outside the Australian Open. Halfway to a career Grand Slam, one notes.
But wait. It is not the final Sunday yet. Not an anticipated showdown with Nadal or the opportunity of facing someone other than Nadal for the title. Right now, it is the opening Friday, it is the third round, and it is del Potro.
Somehow, that name does not quite fit. Del Potro is no third-round opponent; he's a former U.S. Open champion and declared future of the game. Along with Djokovic, he is the only player other than Nadal and Federer to win a Grand Slam since the 2005 Australian Open.
This premature collision is the result of del Potro's low ranking, caused by wrist problems that required surgery a year ago. He sputtered when coming back last fall and started the year slowly, but the 22-year-old has made strides since then. He has won two smaller titles and not lost to anyone ranked outside the top 10 since January, except Mardy Fish in the Miami Masters, with Fish now inside the top 10.
Though his biggest wins have been on hard courts, del Potro is no slouch on clay. The last time he appeared at Roland Garros it was 2009, and he was up two sets to one against Federer in the semifinals. Federer would battle back from a fifth-set deficit and go on to win the title; del Potro would go on to get his revenge against Federer in the U.S. Open final later that year.
After not being here last year because of injuries, del Potro hopes to pick up where he left off. "The mistakes I made in 2009 during the fifth set at the crucial moment in the match against Federer are mistakes I'll try and avoid on Friday," he said.
He looked to be recapturing some of that form this spring, winning Estoril and setting up an anticipated matchup with Nadal in Madrid before a hip injury forced him to withdraw.
It was another frustrating physical setback for the injury-prone 6-foot-6 Argentine, creating doubts about whether he would even be able to play this event. But it does mean he comes in with a little nine-match winning streak of his own -- seven before the injury and two fairly convincing performances in his first two rounds here.
Impressive, but it certainly doesn't match Djokovic's run.
It does signal that del Potro is ready to test the Serb in Friday's encounter. He is one of the few players whose game is big enough to potentially unsettle Djokovic's current groove, and he has both the boldness of youth and the experience of playing big matches. He is respectful but not overawed at the prospect of facing Djokovic and the streak. "He's the favorite for the next match and for the tournament. But I will try to be ready for fight," said the mild-mannered Argentine.
The two are friendly off the court, but too much is at stake for them to give up anything in this match. If Djokovic is playing for a chance at history, del Potro is playing to announce himself as a major contender and put his recent stretch of injuries behind him.
After surgery last year, del Potro had serious doubts about whether he would ever be able to compete effectively again, and he is experiencing keen pleasure in simply being able to take part in these occasions again.
"It's special he's trying to make a record here, to be No. 1, also," said del Potro. "I'm great friend of him. We have very good relationship."
Will there be a wager on the match? "Of course not," he replied, to the relief of the tennis integrity unit. "He's much richer than I am."
The fun-loving Djokovic took the bait. "I will accept any bet," he laughed. "Why not? We can have fun.
"He's a great guy. We have a really friendly relationship off the court, and regardless what happens, we'll still stay friends, and, of course, I mean, we're both professional. We want to win on the court. If the bet is a dinner, I will do my best to earn the dinner."
Despite the stakes, Djokovic sounded enthusiastic rather than worried about the clash. Perhaps it's the fact that he has won all three of their previous meetings. Or perhaps, after six months, he has simply forgotten what it is to lose.
"It's going to be a great match, a battle, and he has always had a quality to be at the top of the men's game," said Djokovic. "He is playing equally well on any surface. Big serve, great groundstrokes. For his height he's moving really well. He's just overall a top player for me.
"It's going to be a big challenge for both of us, obviously a great match for people to see."
Kamakshi Tandon is a freelance tennis writer for ESPN.com.