Nadal, Djokovic among Shanghai winners

SHANGHAI, Oct. 15 (UPI) -- World No. 2 Rafael Nadal and No. 4 Novak Djokovic each won in straight sets Thursday in the third round of the $5.3 million Shanghai ATP Masters in China.

Nadal took out Tommy Robredo 6-1, 6-4 by winning nearly as many points (28-29) off Robredo's serve as Robredo did. Djokovic had five aces and dropped serve just once in a 6-4, 6-2 win over Rainer Schuettler in his match.

Two players retired from matches because of injuries Thursday. No. 11-seeded Gael Monfils trailed 6-2, 3-0 to Ivan Ljubicic when back problems caused him to quit. Stanislas Wawrinka was in the third set of a match with No. 13-seeded Radek Stepanek when stomach problems forced him out. Five players have left matches at Shanghai because of injuries.

Ljubicic advanced to Friday's quarterfinals against Nadal while Stepanek next goes against sixth-seeded Nikolay Davydenko, who beat No. 10-seeded Fernando Gonzalez 6-3, 7-5 on Thursday.

Djokovic's quarterfinal foe is eighth-seeded Gilles Simon, who ousted Tomas Berdych 6-3, 6-4 in the third round.

Friday's fourth match sends ninth-seeded Robin Soderling against Feliciano Lopez. Soderling on Thursday continued his recent strong play with a 6-3, 6-3 upset of fifth-seeded Jo-Wilfried Tsonga while Lopez advanced 5-7, 7-6 (7-3), 6-1 at the expense of Jurgen Melzer.