Four-time titlist Roger Federer, three-time runner-up Novak Djokovic and Juan Martin del Potro were all quarterfinal winners at the $2.825 million Western & Southern Open, the seventh of nine ATP Masters events this year.

The Wimbledon champion and Olympic silver medalist Federer is the tournament's top seed. The Swiss native got past 10th-seeded Mardy Fish 6-3, 7-6 (7-4). Fish is a two-time Cincinnati runner-up, including a loss to Federer in the final here two years ago.

Federer advanced to face fellow countryman Stanislas Wawrinka, who outlasted Canada's Milos Raonic, 2-6, 7-6 (7-5), 6-4 on Friday.

The second-seeded former world No. 1 Djokovic whipped 12th-seeded Croat Marin Cilic 6-3, 6-2 on Day 6. The Serbian star advanced in 1 hour, 21 minutes with the help of seven aces.

The reigning U.S. and Australian Open titlist Djokovic, who lost to British star Andy Murray in last year's Cincinnati finale, is fresh off his Masters title in Toronto last week.

Djokovic will meet del Potro in Saturday's semifinals in a rematch of their Olympic bronze-medal match from two weeks ago, which was won by the towering Argentine.

Enjoying his best-ever showing this week in Cincinnati, the sixth-seeded del Potro swatted French lucky-loser Jeremy Chardy 6-1, 6-3 Friday on the hardcourts at the Lindner Family Tennis Center. Del Potro fired eight aces and was not broken in the 1-hour, 16-minute affair.

Chardy stunned the defending Cincinnati champion and Olympic gold medalist Murray in the third round here on Thursday.

The 6-foot-6 del Potro is a former U.S. Open champ who captured his bronze medal at the London Games earlier this month.