NEW YORK, Aug 25, 2025 (BSS/AFP) - World number one Aryna Sabalenka overcame a shaky start before asserting her dominance to reach the second round of the US Open on Sunday, defeating Switzerland's Rebeka Masarova in straight sets.

Defending champion Sabalenka -- bidding to become the first woman to win back-to-back US Open titles since Serena Williams in 2014 -- prevailed 7-5, 6-1 at the Arthur Ashe Stadium.

Sabalenka though did not have it all her own way, surrendering an early break in the first set to trail 3-2.

But the Belarusian ironed out the kinks in her game rapidly, breaking back to level at 3-3, and then breaking again to take the first set.

Sabalenka trailed 0-40 on her opening service game of the second set, but flipped a switch to recover and hold before racing into a 5-0 lead.

Masarova held to delay the inevitable but Sabalenka duly closed out victory.

The 27-year-old will face unseeded Russian Polina Kudermetova in the second round.