World No. 1 Novak Djokovic, who suffered an ankle injury during the Davis Cup World Group quarter-finals with the United States, said his participation at the Monte Carlo Masters was uncertain, media reported Monday. "The season on the clay begins... I would like to play in Monte Carlo, where I live. I love that tournament, I am optimist, but I do not know if it is realistic," Djokovic was quoted as saying by Serbia's Beta News Agency. Talking about his injury, Djokovic said he had "avoided the worst degree of distortion".

World No. 1 and Australian Open champion Novak Djokovic's victory over Sam Querrey of the United States on Sunday advanced Serbia into the semi-finals of the Davis Cup. Djokovic, who had to battle through an ankle injury he suffered in the opening set, earned a 7-5, 6-7 (4/7), 6-1, 6-0 win to give the Serbians an insurmountable 3-1 lead in the best-of-five tie against the Americans. It is the second win for Serbia in four years over the 32-time titlist USA. In their only other previous Davis Cup encounter Serbia defeated the Americans in Belgrade in 2010.

Results from the second day of the Davis Cup World Group quarter-final tie between the United States and Serbia on Saturday: USA 1 Serbia 2 Novak Djokovic (SRB) bt John Isner (USA) 7-6 (7/5), 6-2, 7-5 Sam Querrey (USA) bt Viktor Troicki (SRB) 7-6 (7/1), 3-6, 4-6, 6-1, 6-4 Saturday Nenad Zimonjic/Ilija Bozoljac (SRB) bt Bob Bryan/Mike Bryan (USA) 7-6 (7/5), 7-6 (7/1), 5-7, 4-6, 15-13 Sunday Sam Querrey (USA) v Novak Djokovic (SRB) John Isner (USA) v Viktor Troicki (SRB) afp

Results from the first day of the Davis Cup World Group quarter-final tie between the United States and Serbia on Friday: USA 0 Serbia 1 Novak Djokovic (SRB) bt John Isner (USA) 7-6 (7/5), 6-2, 7-5 Playing later Sam Querrey (USA) v Viktor Troicki (SRB) Saturday Bob Bryan/Mike Bryan (USA) v Nenad Zimonjic/Ilija Bozoljac (SRB) Sunday Sam Querrey (USA) v Novak Djokovic (SRB) John Isner (USA) v Viktor Troicki (SRB)