World number two Rafael Nadal reached the third round of the Shanghai ATP Masters with a hard-fought win over James Blake.

Nadal, the top seed, overcame his American opponent 6-2 6-7 (7-4) 6-4 in a little under two and a quarter hours to claim his second victory over Blake in a week following his win at the China Open in Beijing.

The 23-year-old will now meet fellow Spaniard Tommy Robredo, the 14th seed, who saved three match points in the second set tie-break to defeat qualifier Florian Mayer of Germany 4-6 7-6 (10-8) 6-4.

Third seed and US Open champion Juan Martin del Potro was forced to retire with a right wrist injury in his match with Jurgen Melzer with the Austrian leading 7-5 2-1.

Melzer will now meet Spaniard Feliciano Lopez after the Spaniard beat number 16 seed David Ferrer 4-6 7-5 6-1.

Fifth-seeded Frenchman Jo-Wilfried Tsonga and ninth seed Robin Soderling of Sweden will meet in the third round tomorrow with both players attempting to qualify for the ATP World Tour Finals.

Tsonga had a straightforward 6-3 6-3 victory over Chinese wild card and world number 393 Shao-Xuan Zeng in 61 minutes on Wednesday.

Soderling beat Nicolas Almagro of Spain 6-4 7-5 in a match marked by big serving.

Tomas Berdych recorded his first win in three meetings against Russian wild card Marat Safin by a 3-6 6-4 6-4 scoreline although the match ended in some controversy when Safin refused to shake his opponent's hand.

Berdych will next meet eight-seeded Frenchman Gilles Simon who beat Viktor Troicki 6-3 6-4.

Rainer Schuettler was a set up when his fellow German Tommy Haas retired.

In the final match, Novak Djokovic eased through without a problem after beating Fabio Fognini 6-3 6-1.