Learner Tien, Daniel Merida advance to quarterfinals in Montreal

Young ATP tour pros Learner Tien and Spain's Daniel Merida both won convincing victories on Sunday at the National Bank Open in Toronto and will meet in a Tuesday quarterfinal match.

The 12th-seeded Tien knocked off Argentina's Thiago Agustin Tirante, 6-4, 6-4, while Merida defeated weary Dutchman Tallon Grieskpoor, 6-3, 6-1.

Tien, 20, has earned his second quarterfinal appearance at a Masters 1000 event, having reached the final eight at Indian Wells in March of this year.

Tirante broke Tien in the match's opening game, but the Californian returned the favor in the fourth game. The two remained on serve until an eight-point 10th game, when Tien broke to capture the first set.

Tien, who won on the clay in Geneva in May at an ATP 250 event, served for the match at 5-3, but Tirante broke at love. Undaunted, Tien won the first three points in the following game and closed out his opponent on an unforced error.

The match featured a combined 49 winners, but 67 unforced errors. Tien didn't come to the net often, but did win 11 of 12 points.

"I thought during rallies it was tough because it was really windy today," Tien said. "I felt like the ball was swirling in every rally. I saw the ball well on return."

The rapid-rising Merida, 21, reached his first ATP quarterfinal by relying on an efficient first serve in the win over Griekspoor. The Spaniard won 25 of 30 first serve points over his Dutch rival.

Merida won never broken and delivered 18 winner to only nine unforced errors. Griekspoor committed 29 errors and only recorded 13 winners.

The match only took 69 minutes to complete.

"I feel amazing playing here. I knew I have the level after winning my first title a few weeks ago (at Umag) and I am just aiming to give 100 per cent every point," said Merida. "I try to play solid on my backhand and I think I've always had a good backhand. I try to hit it as much as possible and here it feels really great."

The final round-of-16 matches on Sunday evening feature No. 5 Ben Shelton taking on No. 22 Brazilian Joao Fonseca and Botic van de Zandschulp of the Netherlands facing No. 13 Czech Jakub Mensik.

--Field Level Media