Former world No 1 Lleyton Hewitt cut big-serving American John Isner down to size with a 6-2, 6-4 victory in the first round of the $3.24 million Shanghai Masters yesterday.

The 28-year-old Australian, back at No 23 in the world after sliding outside the top 100 following hip surgery, is nearly a foot shorter than the 6ft 9in (206cm) Isner but came up with some fine returns to disarm the Floridian.

Isner managed just five aces and racked up a whopping 37 unforced errors, leaving Hewitt to seal a second-round tie against Gael Monfils or Paul-Henri Mathieu when the big American netted after 76 minutes.

"He's had a lot of success earlier in the year ... beating guys like (Andy) Roddick over five sets so I knew it was going to be a tough match," said Hewitt.

John Isner of the United States throws his racquet after losing a point against Lleyton Hewitt of Australia at the Shanghai ATP Masters 1000 tournament in Shanghai yesterday. Hewitt won 6-2, 6-4. AP

"It's a matter of just taking your chances when you get into it against those guys and I did that exceptionally well today."

Hewitt, who had one of the biggest wins of his career in Shanghai at the 2002 Masters Cup, believes he could still win another Grand Slam title to add to his US Open and Wimbledon triumphs.

"I've got better as the year has gone on," he said. "My hip's got a lot stronger and better as well.

"I think in the majors this year, that's when I've played my best tennis, and it's taken the best guys in the world to beat me in all four majors this year."

Sixth seed Nikolay Davydenko was the first man to reach the third round when he beat fellow Russian Igor Kunitsyn 6-4, 6-2 with a minimum of fuss on the grandstand court newly built for this year's tournament.

Davydenko reached the final of the last version of the Masters Cup tour championship here last year and is in the running for one of three spots still up for grabs at the season finale in London next month.

Tommy Haas, the 15th seed, also beat a compatriot to take his place in the second round, the 7-6, 6-4 win over Benjamin Becker earning him a tie against another German, Rainer Schuettler.

Also yesterday, Andy Roddick's body finally gave up on him when he limped out of the Shanghai Masters after retiring in the first set of his second-round match against Swiss Stanislas Wawrinka.

The 27-year-old fourth seed, who launched a scathing attack on the grueling tour schedule on Monday, was 4-3 up and looking to convert a break point when he pulled up short chasing a Wawrinka backhand.

The American, who retired with an injured shoulder in his only previous tour clash with the Swiss, also lost the first match of his title defense in Beijing last week. On Monday, he called for the ATP to allow the top players a break in the season or risk curtailing the careers of top players like Roger Federer and Andy Murray.