Katie Boulter is through to the second round of the Japan Open after overcoming a rain delay to win in straight sets against home favourite Himeno Sakatsume.

Boulter led by a set and by 3-1 in the second set when play was suspended on Monday as a result of poor weather in Osaka.

But she picked up where she left off when play resumed on Tuesday, winning 6-3 6-1 to set up a second-round meeting with Switzerland’s Viktorija Golubic.

She said: “Yesterday was a tough spot to end at. I wanted to play last night and continue but with the rain, unfortunately, that wasn't possible. It meant that I had to have the same mindset again today and just try to get over the line and focus on getting through the match.

“I think I did that. I didn't want to be out here playing a third set so I'm pleased with today.”

Boulter, who has been replaced by Sonay Kartal as British No 1 after the 24-year-old’s brilliant run to the Wuhan Open final, saved 12 of 13 break points against the Japanese wildcard as she bounced back from a first-round defeat in Wuhan.

Elsewhere Iga Swiatek is set to miss out on the WTA Finals for the first time since 2020 after she withdrew from the Ningbo Open due to a thigh injury.

The six-time grand slam champion was hampered by the injury during her semi-final defeat to compatriot and eventual champion Maja Chwalinska in Wuhan last week.

The Pole, who won the season-ending Finals in 2023, needed to reach at least the quarter-finals in Ningbo in order to keep her chances of qualifying for the tournament alive, although she could still make the cut to travel there as one of two alternates.

She sits ninth in the rankings race for the event in Indian Wells, which is determined by points totals over the course of the season. Karolina Muchova, who is also not competing at the WTA 500 tournament in Ningbo, and Marta Kostyuk are vying for the final spot.