SHANGHAI, China — Novak Djokovic ended his Masters Cup jinx on Sunday, overcoming a rash of errors to defeat Juan Martin del Potro 7-5, 6-3 in the season-ending tournament.

Nikolay Davydenko used his strong ground game to rally past Jo-Wilfried Tsonga 6-7 (6), 6-4, 7-6 (0) in the other round-robin match.

Djokovic failed to win a set last year in three matches, citing exhaustion from a heavy schedule in his rise to No. 3 in the world. The Serb also lost in the round of 16 in his past two tournaments.

"I was a bit intimidated by the fact of not winning a single match last year, that's for sure," Djokovic said. "But this year is different. I feel more confident, stronger player on the court, more mature.

"I used maybe a little bit of my experience. In important moments, I played my best tennis."

Tsonga got off to a shaky start, falling behind 0-40 in his first service game before coming back to hold. Those turned out to be the only break points in the first set.

Tsonga, a newcomer at the Masters Cup like del Potro, quickly won over the fans with his go-for-broke style, even leaping the net while unsuccessfully trying to track down a deft Davydenko drop shot in the tiebreaker.

Davydenko, appearing at the Masters Cup for the fourth straight year, fended off two set points while trailing 4-5. But the Frenchman ripped a service winner to set up his third opportunity. Davydenko had an easy chance to level again, only to whack a high backhand volley into the net.

In the second set, Tsonga faltered while serving at 4-5. He just missed a forehand passing shot to give Davydenko a set point, which the Russian converted with a winner on the baseline.

That briefly seemed to deflate Tsonga, and Davydenko broke him while racing to a 3-0 lead in the third set.

Tsonga staved off a match point with a gutsy drop shot from the baseline that Davydenko couldn't get back while serving at 2-5.

Tsonga rallied to a tiebreaker, but didn't win a point.

"He was lucky in that third set and unlucky in the tiebreak," Davydenko said.

Tsonga gave credit to his opponent.

"It was a tough match," Tsonga said. "He was just better than me at the end. Like we saw at the tiebreak ... he was better physically."

The Red Group, which includes Federer, Andy Murray, Andy Roddick and Gilles Simon, will play Monday in the tournament that features the top eight players.

Top-ranked Nadal withdrew from the event because of tendinitis in his right knee.