NEW YORK, United States (AFP) — Two-time defending champion Aryna Sabalenka rallied in the final set to beat Linda Noskova in a match tiebreaker on Tuesday and reach a sixth straight US Open semi-final.

Sabalenka triumphed 7-6 (7/1), 3-6, 7-6 (10/7) over the 21-year-old Wimbledon champion, striking 42 winners but converting just two of her nine break point chances against the resilient Czech in a fierce duel on Arthur Ashe Stadium.

Trailing 4-2 in the third, Sabalenka appeared headed for another Grand Slam disappointment in a season in which she has so far been unable to add to her stash of four major titles.

Clearly frustrated, Sabalenka nevertheless regrouped and broke Noskova to love to pull level at 4-4. They hurtled to the tiebreaker — where Sabalenka dropped the first two points before climbing back and finally sealed victory with a courageous second-serve ace.

Noskova fired 18 aces — 46 winners in all — as she became the first player to take a set off Sabalenka in the tournament.

“What a battle,” Sabalenka said. “I was pushing myself to the limit in this match especially in the third set.

“I honestly thought the match was over and that’s what helped me to feel loose and go for my shots.”

Sabalenka has now won 18 straight matches at Flushing Meadows, and she must keep going to a third straight title if she is to have a chance to retain the world number one ranking she has held since October of 2024.

The victory was Sabalenka’s first win over a top-10 player since she beat Coco Gauff in the Miami final in March.

That was her third title of 2026, but Sabalenka has struggled since, exiting early at both Roland Garros and Wimbledon.

The Belarusian will next face the winner of the all-American quarter-final between third seed Jessica Pegula and Emma Navarro.

Pegula is among the trio of players who arrived at Flushing Meadows with chance to seize Sabalenka’s number one ranking.

A two-time winner on the WTA tour this year, 2024 finalist Pegula would have to win he first Grand Slam title to have a shot at the top spot.

She reached the US Open final in 2024 and owns a 4-0 career record over 26th-seeded Navarro.

Men’s defending champion Carlos Alcaraz faces his toughest test of the tournament, taking on eighth-seeded American Ben Shelton for a place in the semi-finals.

Shelton expects to face a full-strength Alcaraz despite the fact that the seven-time Grand Slam champion is playing his first tournament in more than four months after recovering from a right wrist injury.

Alcaraz, who completed a career Grand Slam with his Australian Open triumph in January, has improved with every match and will likely need to do so again against Shelton, who is the leading contender to end American men’s 23-year Grand Slam title drought.

Two more Americans face off in Tuesday’s other men’s quarter-final, with charismatic 11th seed Frances Tiafoe taking on 22-year-old Alex Michelsen.