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 on Tuesday.

The 27-year-old fourth seed, who launched a scathing attack on the gruelling 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 a injured shoulder in his only previous tour clash with the Swiss, also lost the first match of his title defence 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.

Gael Monfils, who crushed fellow Frenchman Paul-Henri Mathieu 6-2 6-2 in 54 minutes, will face Lleyton Hewitt who beat Juan Martin del Potro.

Sixth seed Nikolay Davydenko was the first man to reach the third round when he comfortably beat fellow Russian Igor Kunitsyn 6-4 6-2.

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 the three spots still up for grabs at the new season finale in London.

Chile's Fernando Gonzalez, currently in the eighth and final spot in the race to the World Tour Finals, will play Davydenko in the last 16 after beating Brazilian qualifier Thomaz Bellucci 6-3 6-4.

Swede Robin Soderling is another in the hunt for a place in London and the ninth seed helped his cause with a 6-3 6-4 first-round win over Romanian Victor Hanescu.