Double Olympic champion Andy Murray bucked the upset trend as the Scot reached the quarter-finals of the ATP-WTA Cincinnati Masters, winning his 600th career match.

Murray's 90-minute victory on Thursday contrasted with the upset losses suffered by elite rivals Rafael Nadal and Stan Wawrinka, both of whom exited in the third round.

Top seed Murray is chasing the number one ranking of absent Novak Djokovic with the US Open approaching on August 29.

Nadal, seeded third, hit the wall with injury and Olympic fatigue, losing to Croatian teenager Borna Coric 6-1, 6-3 on Thursday.

Second seed Wawrinka slumped to a 6-4, 6-4 defeat to Grigor Dimitrov as the Bulgarian, fighting his way back after a poor season, reached the Cincinnati quarter-finals for the fourth time.

Murray is thrilled to have won 600 matches as he continues his momentum from Rio.

"I've  played a lot of matches, 600 is obviously a lot. I never expected to be in this position when I started," he said.

"It was good to do it here, where I got a wild card when I was 18. I also won my first Masters 1000 title here (in 2005). To win my 600th here is cool."

Murray on Friday plays Bernard Tomic after the Australian upset fifth seed Kei Nishikori 7-6 (7/1), 7-6 (7/5).

"He had a good win today," Murray said. "He's a talented player, I've had some good matches against him.

"He's moving up the rankings, there should be some good points."

Nadal, who won gold in the Olympic doubles, committed 18 unforced errors and four double faults in the first set alone.

"I came here, I tried. I tried to do the right things to be ready, but it was obvious that I was not ready today," Nadal said.

Coric took complete control of Nadal as he won 10 games on the trot to lead 4-0 in the second set before wrapping up a crushing victory in 72 minutes.

For Coric, ranked 49th, it was just his second career win over a top-five player and also snapped a 10-match losing streak against opponents in the top 10.

"It was an unbelievable match from my side," said the Croat. "I played well from the beginning and he was not playing his best tennis. 

"I served well and was hoping for some aces. That's what saved me."

Second seed Wawrinka, coming off a back problem which kept him from Rio, did not help his own cause with 28 unforced errors and just 11 winners in a contest that finished inside 90 minutes.

- Raonic rolls over Sugita -

Fourth seed Milos Raonic dispatched Japan's Yuichi Sugita 6-1, 3-6, 6-1 with 17 aces. 

Steve Johnson replaced John Isner as the top-ranked American thanks to a 6-3, 7-6 (8/6) upset of French seventh seed Jo-Wilfried Tsonga. Ninth seed Gael Monfils withdrew with back pain, handing a quarter-final place to Dominic Thiem.

In the women's third round, second seed Angelique Kerber beat Barbora Strycova 7-6 (7/5), 6-4 to keep hopes of earning the number one ranking alive if she can lift the title.

Simona Halep beat Australian Daria Gavrilova 6-1, 6-2 while seventh seed Svetlana Kuznetsova beat Swiss Timea Bacsinszky 6-2, 3-6, 6-2.

Ninth seed Carla Suarez Navarro beat US Open finalist Roberta Vinci 6-1, 7-5. Karolina Pliskova stopped Misaki Doi 7-5, 6-3.

Source: AFP