NEW YORK (AP) — Pablo Carreno Busta ended Canadian teenager Denis Shapovalov’s run in the U.S. Open, winning three tiebreakers Sunday to advance to the quarterfinals.

The No. 12 seed won 7-6 (2), 7-6 (4), 7-6 (3) to reach the quarters for the first time at Flushing Meadows and match his best result in a Grand Slam tournament. The Spaniard also went to the quarterfinals at the French Open in June, losing to eventual champion Rafael Nadal.

The 18-year-old Shapovalov was bidding to become the youngest U.S. Open men’s quarterfinalist since Andre Agassi was also 18 in 1988. But he blew a 5-2 lead in the first set, when Carreno Busta erased three set points before building a big lead in the tiebreaker, and couldn’t overcome 55 unforced errors.

Carreno Busta had never been past the third round here until this year and is suddenly the favorite in his half of the draw, by seed, to the reach the final. He next faces either No. 16 Lucas Pouille or No. 29 Diego Schwartzman.

That will be his first time in this tournament he won’t face a qualifier. Nobody had ever faced four in a row at any Grand Slam event.

Of course, Shapovalov is not the normal qualifier. He has been one of the hottest players in men’s tennis late this summer, knocking off Nadal in Montreal when he became the youngest player to reach the semifinals of a Masters 1000 event.

He upset No. 8 seed Jo-Wilfried Tsonga in the second round and left to a loud ovation after finally falling Sunday under the roof at Arthur Ashe Stadium.

No. 17 seed Sam Querrey, the only American left, faced No. 23 seed Mischa Zverev at night. No. 8 Kevin Anderson of South Africa met unseeded Paolo Lorenzi in the other fourth-round match in that half of the bracket, which after injuries and upsets will produce a first-time finalist in a Grand Slam tournament.

The power players Sunday were on the women’s side.

Former U.S. Open champions Maria Sharapova and Venus Williams were in action, while No. 3 seed Garbine Muguruza faced No. 13 Petra Kvitova in a matchup for former Wimbledon champions.

No. 9 seed Williams faced Carla Suarez Navarro of Spain, after Sharapova met 16th-seeded Anastasija Sevastova of Latvia.

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