Ben Shelton took another step toward defending his ATP Montreal Masters title on Tuesday with a 6-3, 6-1 quarter-finals hammering of Jakub Mensik for his 10th straight victory in Canada.
World number 10 Shelton, the last top-10 player in the field, was never challenged by the Czech in advancing to a Wednesday semi-final against fellow American Learner Tien, who ousted Spain's Daniel Merida 6-3, 6-2 in 72 minutes.
"It was a great performance for me, super happy with that and to be in the semis again," Shelton said.
Spanish teen Rafael Jodar booked a semi-final spot in only his fifth ATP Masters 1000 event by holding off France's Arthur Fils 7-6 (7/5), 6-3.
The 19-year-old will face the oldest remaining player when he plays 25-year-old American Brandon Nakashima in a Wednesday battle for a place in Thursday's final.
Nakashima reached his breakthrough Masters semi in 77 minutes as he imposed his game on Luciano Darderi 6-2, 6-3, setting up three match points with his 11th ace as winning as the Italian missed on a drop shot.
It's the first time since 1992 that three American men have reached the last four in Canada.
Shelton was on fire in his 72-minute thrashing of Mensik, the American producing 18 winners and only three unforced errors.
"I felt great, I played well form the ground from point one," Shelton said. "I'm right where I want to be. I maintained a high level throughout the match. I hope to continue to build on this in the semis."
Jodar shrugged off a slight tweak of his ankle in the second set against Fils and remained calm throughout as his French opponent smashed a racquet after being broken early in the second set.
Jodar, who does not turn 20 until after the US Open, has won 34 matches this season and risen to 15th in world rankings, but sees improving his game as more important than his ranking.
"That shouldn't be your primary thing and your goal," he said. "My goal is to have fun on court and to enjoy all the tournaments that are new for me."
Fils, back after injury, saved three match points in the final game before Jodar lanced a winner to the empty court after an hour and three-quarters.
"I played a very high level today against a tough player like Arthur," Jodar said. "I had to give my best to win this match."
Nakashima, who won his fifth quarter-final of the season, credited his serve with the win.