Roger Federer won two matches on a hectic Friday in Cincinnati and had to come from behind to account for Stan Wawrinka.
The Cincinnati Masters on Friday made up for time lost to bad weather, as the likes of Roger Federer and Novak Djokovic both played twice.
Stan Wawrinka offered the strongest indication yet that a knee injury is finally behind him, but he was not able to halt Roger Federer.
Rain wreaked havoc again as only three matches were completed at the ATP Masters 1000 tournament on Thursday.
While Novak Djokovic and Grigor Dimitrov won in Cincinnati on Wednesday, Alexander Zverev said goodbye.
The wildcards for the US Open have been announced, with Stan Wawrinka and Victoria Azarenka both included at Flushing Meadows.
Former world number one Novak Djokovic was pushed by Steve Johnson after Andy Murray lost his first-round match on Monday.
Top seed Rafael Nadal reached the last eight after outlasting Stan Wawrinka in an absorbing contest at the ATP 1000 tournament.
It was a masterclass in Toronto, where Rafael Nadal came out on top 7-5 7-6 (7-4) after more than two hours of scintillating tennis.
Benoit Paire showed signs of life late but world number one Rafael Nadal advanced to the last 16 in straight sets at the ATP 1000 event.