Novak Djokovic: Back injury is not serious

By the Associated Press | September 19, 2011 | 9:55 AM EDT

Novak Djokovic of Serbia, center, reacts after retiring from a match against Juan Martin Del Potro of Argentina at the World Group Davis Cup semifinals tennis match in Belgrade, Serbia, Sunday, Sept. 18, 2011. Djokovic retired from the match after getting injured in the second set. Argentina won the overall duel and will advance to the Davis Cup finals. (AP Photo/ Marko Drobnjakovic)

BELGRADE, Serbia (AP) — Novak Djokovic says the back muscle injury that forced him to quit his Davis Cup match is not serious but requires rest.

Djokovic tried to play through the pain Sunday against Juan Martin del Potro in the semifinals. But the top-ranked Serb stopped during the second set, sending Argentina to the Davis Cup final against Spain.

Djokovic says the injury is "not as serious as we have thought. It's a partial rupture of a back muscle that deserves rest."

Djokovic skipped Friday's opening singles because of lingering back problems following his victory over Rafael Nadal in the U.S. Open final. But after losing the opening set 7-6 (5) against Del Potro, Djokovic fell to the floor in pain during the third game of the second set.