US Open : Men's Day Nine Roundup

Rafael Nadal reclaimed the world number two ranking and stormed into the quarter-finals with a four-set victory over Gael Monfils.
Nadal's victory, combined with Murray's shock fourth-round defeat in a tournament the Briton had reached the final in 12 months ago, meant the Spaniard regained the number two spot but that was just an added bonus as he kept alive his dream of completing a career grand slam at the age of 23.
Nadal came from a set down to France's 13th seed to win 6-7 (3-7) 6-3 6-1 6-3 and set up a last-eight meeting with Chile's Fernando Gonzalez, the 11th seed, who had handed the French their first defeat of the night with a four-set win over seventh seed Jo-Wilfried Tsonga.
A superb display of power tennis sent Juan Martin Del Potro into the quarter-finals at Flushing Meadows for the second year running.
The sixth seed slammed down 22 aces as he ended the run of the in-form Juan Carlos Ferrero with a 6-3 6-3 6-3 victory.
As well as his impressive serving display - Del Potro did not drop his serve in the match - the Argentine was excellent from the baseline, showing again that he possesses some of the most powerful groundstrokes in the game.
Ferrero competed as well as he could, but Del Potro always looked like he had a little extra in reserve as he set up a meeting with Andy Murray's conqueror, Marin Cilic.
Afterwards Del Potro expressed his surprise that he would be facing Cilic and not Murray.
"Cilic has everything to be a good player," Del Potro said. "But Murray is number two, winning everywhere.
"So maybe everybody is surprised but Cilic has very good weapons. If he beat Murray he's confident and it will be a very tough one for me."
Ferrero, however, believes Del Potro can win that match and indeed challenge for the title.
Asked if he could go on to win the tournament, Ferrero said: "Yeah, I think he's playing at a level to win a Grand Slam. I mean, I think he can play against anybody here - the guys who are in quarter-finals right now.
"He has to play against Cilic right now. I think this is a chance for him to get into the semis."
Source : Star sports