Il Nuovo Postiglione - Clay-courter Merida on hardcourt learning curve in Montreal

The world number 63 joins compatriot Rafael Jodar in the Canada quarter-finals and will break through to a career-best spot inside the top 50 as a result of his fourth-round victory.

Prior to making his Montreal debut, clay-courter Merida had never won a tour-level match on hardcourt.

He will try to extend his streak of cement success to five in a row when he plays a first Masters quarter-final against US 12th seed Learner Tien, who wore down Argentine Thiago Tirante 6-4, 6-4.

Tien, the 12th seed, saved the first eight break points he faced in the second set in a battle of big hitters and secured victory in his fifth match point, with his opponent handing over the final game with four unforced errors.

"Today was humid, conditions are always tough," Tien said. "I'm happy with how the match worked out.

"This was one of those days where I was making good contact with the ball. I was seeing the ball well and returning well."

Against Griekspoor, Merida was deadly with his backhand, leaving the Dutchman flat-footed in the 69-minute triumph.

Spain's title-winner last month on clay in Umag has now claimed 16 victories this breakthrough season.

"It's amazing playing here and giving my 100% in each match," the 21-year-old winner said. "To make a hardcourt quarter-final is great.

"I try to play solid with my backhand, hit it as much as possible and stay calm."

In the evening session, holder Ben Shelton was bidding for the last eight with a match against Brazilian teenager Joao Fonseca.

E.Spicuzza--INP