LONDON -- Roger Federer has broken some of Ivan Lendl's records before. There was the Open era semifinal streak at majors, for one.
With Federer on the verge of tying Lendl for the most wins at the men's year-end championships and passing the eight-time Grand Slam winner and Pete Sampras in men's year-end titles, Lendl wasn't disappointed. In fact, it was the opposite.
"That would be fun to see," Lendl said.
And fun it turned out to be.
When Federer reaches the year-end finals, he usually triumphs (now 6-1), and the Swiss completed the job again against familiar foe Jo-Wilfried Tsonga, 6-3, 6-7 (6), 6-3 in his 100th final.
Federer thus became an unprecedented six-time champion at the most prestigious event outside the majors, eclipsing Lendl and Sampras' haul of five. It was fitting that royalty, or near royalty -- Pippa Middleton, the sister of the Duchess of Cambridge -- witnessed the feat in London.
In recent times, when Federer wasn't having as much success as usual, some questioned his motivation. He's been on the tour for more than 10 years, has a family and already leads the way in Grand Slams.
You could forgive him for losing a bit of interest.
He always maintained the desire was there, though, and his 17-match winning streak to end 2011 means no one should question his hunger for a while. Federer said doubts he had this year that worked against him in close matches had dissipated, too.
"I love this game more than anybody, so I'm not all of a sudden going to wake up in the morning and say I don't like it anymore," Federer said. "It's a lot of effort I have to put in every day. I know that. I do that because what I get in return is moments like today, with my team, with my family. It's priceless."
Motivation aside, Federer's mental toughness and ability to grind out matches (speaking of Lendl) are often overlooked. Federer's game appears so smooth, and he moves with such efficiency on court that it's easy to overlook.
But it shouldn't be ignored, especially during the winning streak.
"When I look at Roger, he's barely sweating," said former top-five pro and ESPN analyst Brad Gilbert. "He plays so effortlessly. And I think that's why you don't think he's a battler as much because it looks so easy to him. It's not like he's changing shirts on the court. He looks so perfect. But he is a battler."
How many players could fail to serve out a massive tussle, blow a 5-2 lead in a second-set tiebreaker already up a set and squander a match point at 6-5 in the tiebreaker, as Federer did against Tsonga, and still win the decider?
Last week, Federer spoke about his ability to keep his emotions in check, and it served him well in that third set. Serving first didn't hurt, either, as he was able to apply scoreboard pressure on Tsonga.
"I had to go through the third set, which was tough, but eventually I made it, which felt probably even better," Federer said.
In the opening set, it was the Frenchman who threatened on Federer's serve in the first seven games -- while dropping one point behind his own serve. Aided, however, by Rafael Nadal-like retrieving, Federer broke for 5-3.
Tsonga concluded the set with more winners, fewer unforced errors, and a higher percentage of points won behind the first and second delivery -- and yet trailed.
Tsonga needed the first set to have a realistic chance of beating Federer, even if he rallied from two sets down against the Swiss at Wimbledon. But Federer won seven of their eight first sets in 2011, putting Tsonga in a hole that on most occasions he couldn't escape.
Tsonga, who was attempting to make history himself by becoming the first Frenchman to win the ATP World Tour Finals, should be encouraged by his week after defeating Nadal, Fish and Tomas Berdych.
He wasn't steady enough, however, versus Federer and the balance wasn't right. Tsonga, without a coach, wasn't sure when to attack or be patient, and his tendency for being a showman cost him as early as the first game.
He erred on the little chances that often lead to big ones, such as on the Federer serve at 3-3, 30-all in the first, or 2-2, 15-30 on the Federer serve in the third.
"I hope he gets a tennis expert on his sights to help him become better because I think he has the game and personality to win majors," said six-time Grand Slam winner Boris Becker, working as an analyst for British TV.
Federer, who has two coaches, will be hoping to carry his fall form into January's Australian Open, where he'll attempt to outgun rivals Novak Djokovic and Nadal, hoping to snap an almost two-year Grand Slam drought.
"For me it was the strongest finish I've ever had in my career, which I'm very proud of," Federer said. "I'm looking forward to next year. I'm really excited."
When Lendl was asked what he has made of Federer's past two months, in the wake of blowing match points against Djokovic at the U.S. Open for the second straight year, he replied: "People tend to overthink all of this. Let's see what happens in Australia."
London-based Ravi Ubha covers soccer and tennis for ESPN.com. You can follow him on Twitter.