Tennis-Stepanek pulls out of Davis Cup opening singles

PRAGUE, July 9 (Reuters) - Czech number two Radek Stepanek has pulled out of Friday's opening singles in the Davis Cup quarter-final against Argentina due to a knee injury.

"Radek (Stepanek) has been having knee problems the whole week," captain Jaroslav Navratil said on Thursday. "We decided ... that he would not play on Friday because there would be too much burden."

Stepanek was still nominated for Saturday's doubles, alongside doubles specialist Lukas Dlouhy, and may play in Sunday's return singles against Juan Monaco if he feels well enough, Navratil added.

World number five Juan Martin Del Potro will lead last year's runners-up Argentina. He will play the second opening singles match against Ivo Minar on Friday.

Czech number one Tomas Berdych will clash with Juan Monaco in the first opening singles match. (Reporting by Martin Dokoupil, writing by Jan Lopatka, Editing by Nigel Hunt)