NEW YORK—Belinda Bencic wore down Donna Vekic and advanced to her first Grand Slam semifinal with a 7-6 (5), 6-3 victory Wednesday at the U.S. Open in New York.

Coming off her upset of top-ranked Naomi Osaka in the fourth round, the 12th-seeded Bencic kept up her big hitting and broke open a close match midway through the second set by winning eight straight points.

Trailing 3-2 in the set, that sent her into the lead and Vekic never recovered, with Bencic winning the final four games to surpass her 2014 run to the U.S. Open quarter-finals for her best performance in a major tournament.

“I just really like the challenge,” she said of playing in big matches. “I think some players are a little bit afraid of the big courts, but for me it’s more motivation.”

Bencic advanced to play No. 15 Bianca Andreescu, the first teen US Open semifinalist in a decade after the Canadian defeated 25th seed Elise Mertens of Belgium, 3-6, 6-2, 6-3.

“I’m honestly speechless,” the 19-year-old Andreescu said. “I need someone to pinch me right now. Is this real life?”

Six-time U.S. Open champion Serena Williams faces fifth-seeded Elina Svitolina in the other semifinal.

On the men’s side, Rafael Nadal tried to make sure the U.S. Open had one member of the Big Three in the semifinals when he faced No. 20 Diego Schwartzman on Wednesday night.

No. 24 Matteo Berrettini downed No. 13 Gael Monfils of France, 3-6, 6-3, 6-2, 3-6, 7-6 (5), to clinch the first semifinal slot.

Vekic, seeded 23rd, was also seeking her first semifinal in a major tournament. But with her face bright red as the sun beat down on Arthur Ashe Stadium, she couldn’t keep up with her friend’s power during the biggest moments of the match.

“I think she was just playing better tennis overall today,” Vekic said. “I felt like I couldn’t get three good points together. I was, like, playing one point good, then bad.”

It was Bencic who cracked first, missing an easy putaway on game point while serving at 4-all in the first set. She momentarily seemed to lose focus, as Vekic then won the next three points to break for a 5-4 lead.

But Bencic broke right back to even it again and eventually they headed to a tiebreaker, where the 22-year-old Bencic has thrived this season. Trailing 2-1, she ran off five of the next six points before eventually wrapping it up to improve to 10-2 in tiebreakers this season.

Vekic recovered to take a 3-2 lead in the second set, but that 10-point fifth game seemed to take a little out of her, with Bencic running off the next eight points to seize the lead.