SHANGHAI — Nikolay Davydenko upset top-seeded Rafael Nadal 7-6 (3), 6-3 on Sunday to win the Shanghai Masters for his fourth title of the year.

The sixth-seeded Davydenko broke decisively in the sixth game of the second set to collect his 18th career title. His flat groundstrokes and angled winners denied the Spaniard a sixth title for this year and his first since the Rome Masters in May.

"I think I was a little bit lucky, but mostly I was playing very well today. I did a good job in three weeks in Asia," said Davydenko, who won in Kuala Lumpur two weeks ago.

Nadal returned last week after a month out due to a pulled stomach muscle at the U.S. Open. He looked rusty, having advanced twice when his opponents retired: Ivan Ljubicic of Croatia in the quarterfinals and Feliciano Lopez of Spain in the semifinals.

Nadal had reached the semifinals at Beijing last week on his return to the tour. The winner of six Grand Slam tournament titles also was sidelined after the French Open for two months with tendinitis in both knees.

"I have my chance in the first set and I am especially happy with one thing — it's the first match after my injury comeback against one top player," Nadal said. "I really felt I really have chances to win.

"That's the most positive thing for me, and I fight all the time with a positive attitude, no physical problems. So that's very good news for me."

He dropped to 5-3 in finals this season and 4-3 head-to-head against Davydenko.

The final point of the match delivered some drama when Nadal's forehand received a late out call by a linesperson. Davydenko thought he won the match, but Nadal challenged the call.

Crouching as he awaited the decision, Davydenko leapt up in victory when the replay showed Nadal's ball had landed long. He then ran to the side of the court to kiss his wife, Irina.

The first set had a number of twists and turns before Davydenko hit a backhand winner down the line to clinch the tiebreaker.

Davydenko took advantage of his third break point in the third game and held it until Nadal broke back in the eighth game.

"Four-all in first set, I was feeling like I losing my chance to win the first set because he came back," Davydenko said. "I play very well in the tiebreak, winning, and then feeling I have a chance."

It appeared that Nadal was taking charge, holding a set point on Davydenko's serve in the 10th game. But he flubbed that point by hitting a casual lob that Davydenko answered with a crisp overhead winner.

From 2-2 in the first set tiebreaker, Davydenko successfully challenged Nadal's serve on the fifth and ninth points to prevail.

In the second set, Davydenko broke Nadal's serve in the sixth game when the Spaniard hit a backhand wide to take a 4-2 lead.

The Russian also won tournaments in Hamburg; Umag and Russia in 2009.