US Open winner Juan Del Potro was heading home to Argentina for treatment after early loss at the Shanghai Masters.

The third-seeded Argentine failed to finish after losing the first set 6-4 against Austrian Juergen Melzer, with Del Potro saying wrist tendinitis will keep him out for several weeks.

Top-seed Rafael Nadal regained his confidence after last week’s Beijing loss, defeating James Blake 6-2, 6-7 (4-7), 6-4 with 30 winners.

Second seed Novak Djokovic, the Beijing champion, easily handled Italy’s Italian Fabio Fognini 6-3, 6-1 in 69 minutes.

“Every match is important for me now, this has been a difficult year for me,” said Nadal. “I was in control, leading in the score but anything can happen at 4-all in the third.

“I think I deserved the win.” Del Potro, a first-round loser against a qualifier in Tokyo last week in his first outing since winning the US Open crown over Roger Federer, said he quit on medical advice.

“I don’t want to risk for the end of the season. It’s a big tournament in Shanghai, very important for me, but if I want to have a good finish this season, I must go home to be in good shape for the last tournaments.

“It’s difficult to play 11 months at a high level, but we know they (ATP) are working on that. We hope for a good change for the future. But we know it’s difficult.” Del Potro said he first experienced the problem last spring in Miami and needed a week or more of rest. But he also said “I don’t think it’s something dangerous.” Elsewhere in the second round, Croatia Ivan Ljubicic upset Spain’s seventh seed Fernando Verdasco 6-4, 7-6 (8-6) while French Open finalist Robin Soderling put out Nicolas Almagro 6-4, 7-5.

Spain’s 14th seed Tommy Robredo eliminated Florian Mayer 4-6, 7-6 (7-1), 6-4.

Frenchman Gael Monfils ended the Asian run for Lleyton Hewitt, with the 11th seed carving out a 4-6, 6-4, 6-2 comeback effort.

Hewitt couldn’t manage an ace and was broken six times in a battle lasting just over two hours.

The Australian folded spectacularly after leading 2-0 in the final set and losing six straight games.

Retiring Marat Safin lost for his last time in China, going down to Czech Tomas Berdych 3-6, 6-4, 6-4.

Safin said Berdych faked an injury during the contest.

“If you’re losing, just be a man and lose as a man. Don’t pretend that you are injured and then you start running around and start to hit winners.

“I mean, what kind of sportsman are you? What kind of man are you?” said the 29-year-old Russian who will retire next month in Paris.

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