Andy Murray benefited from a double-fault by Juan Martin del Potro in the opening tiebreaker and then looked more and more like the world No.1 during a 7-6 (10-8) 7-5 6-0 victory at the French Open.

The third-round match between a pair of past major champions was much tighter than the straight-set scoreline might indicate.

"Yeah, I expected a very tough match. And the first set was very, very important, I think, for the rest of the match. Whoever had won that first set had big momentum," Murray said. "In these conditions, when it's slow and heavy, to be coming back is difficult."

Murray needed nearly three hours to get past the 29th-seeded del Potro at Court Philippe Chatrier under a cloud-filled sky. It was a rematch of the 2016 Rio Olympics gold-medal final won by Murray.

Del Potro had four set points in the opening set but lost each one, including that key double-fault while ahead 7-6 in the tiebreaker.

After Murray converted a third set point of his own when his opponent's big forehand landed barely wide, del Potro rested his head on the net and stayed put for several seconds, the very picture of disappointment.

"Too much frustration," del Potro said. "I couldn't believe I lost that set."

Murray is a three-time grand slam title winner and was the runner-up at Roland Garros a year ago.

He has not had a great season so far, though, particularly on the clay-court circuit leading up to the French Open, but he now has reached the fourth round for the eighth time in 10 appearances in Paris.

"I'm starting to feel better. I was really looking forward to the French Open," Murray said. "I had struggled the last six or seven weeks coming in."

Del Potro, the 2009 US Open champion, was playing at his first French Open since 2012 because of a series of operations on his left wrist. Under constant pressure from an aggressive foe, del Potro had some trouble from Murray's drop shots and wound up making far more unforced errors, 43-28.

Joining Murray in the fourth round is 2015 champion Stan Wawrinka.

The Swiss world No.3 cruised to victory against an out-of-sorts Fabio Fognini, winning 7-6 (7-2) 6-0 6-2 as the Italian's game fell apart after a strong first set.

"It was a very good first set and I was a bit hesitant, but after that I relaxed," Wawrinka said.

"I am playing very well at the moment but we all know how that can go in a grand slam... Each game gets more difficult."

Equally impressive was 2014 US Open champion Marin Cilic, who charged into the round of 16 by dominating Spain's Feliciano Lopez.

The Croatian whipped 31 winners past the Spaniard in a 6-1 6-3 6-3 drubbing to set up a meeting with South Africa's Kevin Anderson.

Anderson, who conquered Australia's Nick Kyrgios in the second round advanced to the fourth round with a five-set win over Briton Kyle Edmund.

Anderson served 24 aces in just shy of four hours as he came from two-sets-to- one down to win 6-7 (8-6) 7-6 (7-4) 5-7 6-1 6-4.

Also winning through was Spanish veteran Fernando Verdasco.

The left-hander blasted 31 winners as he took just 93 minutes to dismiss Uruguayan 22nd seed Pablo Cuevas 6-2 6-2 6-3.

Verdasco awaits either Kei Nishikori or South Korean youngster Hyeon Chung who were at 7-5 6-4 6-7 (7-4) 0-3 with Chung serving for a 4-0 lead in the fourth set when rain stopped play on Saturday.

Also on court and due to finish are American John Isner and Russian Karen Khachanov, with the latter leading one set to love - and French pair Richard Gasquet and Gael Monfils, who are on serve deep in the opening set.

AAP