Aryna Sabalenka continued her bid to become the first player since Serena Williams to win a third consecutive US Open title with a roller-coaster fourth round win over Taylor Townsend on Sunday.

The top seed struggled at times with her serve before battling to a 6-4, 6-3 victory over Townsend, who knocked two seeded players out of the draw. Sabalenka was broken in four of her nine service games. However, the world No.1 managed to weather the storm to pull off a straight-sets victory. A triumph that was partly aided by a series of missed opportunities from Townsend.

“What an incredible player she is approaching the net,” Sabalenka said of her opponent afterwards.

“What a great returner, moving well, very brave. You could see how focused she was, and it was really challenging playing her, especially here (at the US Open).

“I’m happy to get through this really tough opponent.”

The two-time defending champion experienced a bumpy start to her latest encounter on Arthur Ashe against home player Townsend, with the first five games being breaks of serve. It took Sabalenka 27 minutes to hold serve for the first time before storming to a commanding 5-2 lead.

However, the top seed encountered another blip after losing seven out of the next nine points, allowing Townsend to close in on levelling. The world No.96 had a break point to level at 5-5 but failed to convert. Giving Sabalenka enough room to regain her stronghold as she sealed a 6-4 lead with a forehand winner.

Heading into the second frame, Sabalenka fell behind 1-3 before winning five games in a row to seal victory. The turnaround was helped by some lacklustre play from Townsend, who produced a total of 18 unforced errors.

“I was like, ‘okay, you were down the break, just to try to return the serve, and put as much pressure as you can on her,’” Sabalenka said of her second set comeback.

“Basically, I was just trying to stay focused on myself and playing not only point by point, but ball by ball.

“I’m happy that I was able to turn around that second set.”

Sabalenka is yet to drop a set in this year’s tournament. She has now reached the quarter-finals at nine consecutive hardcourt Grand Slam events, which is the sixth highest among female players in the Open Era.

There are still plenty of challenges ahead for Sabalenka as she battles to keep her No.1 status. To do so, she must win the New York title and hope Elena Rybakina loses before the semi-finals.

“I think it’s really important to focus on yourself and just put as much pressure as you can on that side,” she replied when asked about the depth of women’s tennis.

Sabalenka will play either Wimbledon champion Linda Noskova or Marta Kostyuk in the next round.