World number one Novak Djokovic stormed into the semi-finals of the US Open for the 10th consecutive time after France's Jo-Wilfried Tsonga became his third opponent to pull out with an injury here at Flushing Meadows on Wednesday.
After the Serbian defending champion won first two sets 6-3, 6-2, Tsonga faulted twice on the opening point of the third set before eventually retiring with knee injury in the quarter-final contest at Arthur Ashe Stadium.
Earlier, Djokovic's second-round opponent, Jiri Vesely, withdrew from the tournament with a sore left forearm while the man he was supposed to play in the third round, Mikhail Youzhny, pulled out of the tournament after six games due to a strained left hamstring.
Djokovic has now set up a clash against Frenchman Gael Monfils, who reached the last four following a 6-4, 6-3, 6-3 win over compatriot Lucas Pouille.
Meanwhile, second-seed Andy Murray and Stan Wawrinka will also aim to book their place in the semi-finals when they take on their respective opponents in the quarter-final clash later today.