CINCINNATI — Second seed Stan Wawrinka slumped to defeat as Grigor Dimitrov staged a 6-4, 6-4 upset at the ATP-WTA Cincinnati Masters Thursday to reach the quarterfinals.
Wawrinka, coming off a back problem which kept him from the Rio Olympics, fell victim to the Bulgarian who has been fighting back from a poor season.
The Swiss star did not help his cause with 28 unforced errors and just 11 winners in a contest that finished inside 90 minutes.
Dimitrov, playing doubles with Wawrinka this week as the US Open start approaches a week from Monday, stretched his lead in the series to 4-2. The Bulgarian is through to his fourth Cincinnati quarterfinal.
In the women's third round, 15th seed Karolina Pliskova of the Czech Republic defeated Japan's Misaki Doi 7-5, 6-3.
On Wednesday, Andy Murray picked up where he left off at the Rio Olympics with a 6-3, 6-2 defeat of Juan Monaco in the second round.
The top seed and world No. 2 was back on the court Wednesday just 72 hours after winning the gold medal in the men's tennis tournament at the Summer Games.
At one point during Wednesday's match Murray was treated by the trainer for a right shoulder problem.
He next plays South African Kevin Anderson, who beat French 13th seed Richard Gasquet 6-2, 6-4.
Second seed Stan Wawrinka polished off a two-day victory as he takes aim at a return to the year-end season finals in London. The Swiss tennis player — the second seed at the last major tune-up prior to the US Open — defeated 122nd-ranked American teenager Jared Donaldson 2-6, 6-3, 6-4.
The match began Tuesday night but was held up several times due to rain before being postponed late in the evening. Wawrinka now plays Grigor Dimitrov, a winner over 16th seed Feliciano Lopez 5-7, 6-3, 7-6 (8-6).
Olympic doubles gold medalist Rafael Nadal defeated Pablo Cuevas, 6-1, 7-6 (7-4) while there were also victories for No. 4 Milos Raonic and Japanese No. 5 Kei Nishikori.
Raonic hammered a dozen aces, compared to 20 for losing opponent John Isner, as the Canadian beat the American for the first time, 7-6 (7-5), 7-6 (7-5). Nishikori stopped Russian Mikhail Youzhny 6-3, 6-2.
Sixth seed Tomas Berdych eliminated Spain's Marcel Granollers 6-3, 7-6 (7-4).
Jo-Wilfried Tsonga, seeded seventh, ousted American teenager Reilly Opelka 7-6 (7-5), 7-6 (7-3). Eighth seed Dominic Thiem won his first match since late June at Wimbledon, defeating Australian John Millman 7-5, 6-1.
A furious Nick Kyrgios erupted after losing the opening set to Borna Coric, smashing three racquets in quick succession on his way to a 7-6 (7-2), 4-6, 7-6 (8-6) loss to the Croatian.
In the women's draw, Olympic silver medalist Angelique Kerber started with a defeat of Kristina Mladenovic 6-0, 7-5.
Third seed and 2015 finalist Simona Halep started with a 6-3, 6-1 defeat of Annika Beck.
Spanish fourth seed Garbine Muguruza won her first Cincinnati match with a defeat of Coco Vandeweghe 7-6 (7-4), 6-2. US Open finalist Roberta Vinci stopped Tsvetana Pironkova 7-5, 6-3; seventh seed Svetlana Kuznetsova rolled past Alison Riske in a 3-6, 6-3, 6-1 comeback.
Hungarian Timea Babos upset Swiss 13th seed Belinda Bencic 7-5, 6-2. Bencic is still coming back from a wrist injury that forced her to quit a Wimbledon second-round match.
Monfils injury worry
Olympic tennis quarterfinalist Gaël Monfils has pulled out of Cincinnati Masters with a back problem, the organizers said Thursday.
Monfils now has just 10 days to get himself fit ahead of the US Open following an intense Rio 2016, where he was edged by Japan's Kei Nishikori in the quarterfinals.
The world No. 11 said pain was restricting his mobility and that this was not the time to get injured.
