Djokovic, Roddick, del Potro advance at Paris

PARIS (AP) — Andy Roddick and Juan Martin del Potro boosted their chances of qualifying for next month's Masters Cup by winning their second-round matches in straight sets at the Paris Masters on Tuesday.

Third-seeded Novak Djokovic was leading 6-2, 4-3 against Dmitry Tursunov when the Russian retired with an injured right shoulder, seventh-seeded Roddick beat Feliciano Lopez of Spain 6-3, 6-4 and No. 9 seed del Potro beat Mario Ancic of Croatia 6-0, 6-4.

No. 16 Gael Monfils topped Juan Monaco of Argentina 6-4, 6-4 to set up a possible match against top-ranked Rafael Nadal and No. 15 Fernando Verdasco outlasted Tommy Robredo 6-2, 6-7 (6), 6-2.

Tursunov retired against Djokovic after twice needing treatment on his shoulder. Djokovic, the Australian Open champion, hasn't won a title since his third of the year at the Rome Masters in May.