Juan Martin del Potro breezes through to last eight with win over John Isner

The former US Open champion always looked the likelier winner as he set up a meeting with third seed Marin Cilic in the quarter-finals at Roland Garros.

Del Potro's best performance at the venue was a run to the last four in 2009 when he lost in five sets to Roger Federer.

He was helped by a poor performance by Isner, who toiled against his opponent's pace and direction of shot.

Del Potro, regarded as one of the biggest threats to 10-time champion Rafa Nadal at Roland Garros, broke three times and held serve throughout to set up a meeting with either Croatian third seed Marin Cilic after his five-set win over Fabio Fognini.

"I returned very well, it was the key to the match and I broke three times, I also played well on the important points," said Del Potro, who throughout the match heard parts of the crowd chant 'USA, USA!"

"I love playing here in the USA, USA!," he joked.

"We both played good tennis today. It is so special to get to the quarter-finals here, I'm having great days in Paris and I'd like to stay a few more days."