Katie Boulter has reclaimed the British No 1 ranking from Sonay Kartal after advancing to the semi-finals of the Japan Open in Osaka.

Boulter produced a comeback victory over Croatia’s Antonia Ruzic to reach her third semi-final of the season, where she will face Katerina Siniakova.

Boulter trailed Ruzic by a set and a break early in the second, but won 11 of the next 13 games to turn the match around.

Ruzic, the world No 91, broke back as Boulter served for the match, but the Briton steadied to seal a 3-6, 6-3, 6-3 win in almost two hours.

“She’s a really good player, she’s extremely tough to beat and came out extremely well ,” Boulter said after her forehand winner on match point.

“I did extremely well to come back into it in the second set but she was swinging hard and anything I was giving her wasn’t bothering her.

“Credit to her, I had to hang tough and find a way. Actually in the end I started playing a bit better.

“I got a bit lucky in the middle of the second set but I stayed really hard and I did well to stay there.”

The ‘luck’ Boulter referred to was a pair of net-cords, in succession, which led to her breaking ahead 5-3 in the second set.

Boulter’s run in Osaka means she will now re-enter the world’s top 50, rising to at least No 48 in the rankings ahead of tomorrow’s semi-final.

Kartal had risen to No 50 in the world after her stunning run to the biggest final of her career at the Wuhan Open, a WTA 1000 event, last week.

The 30-year-old Boulter will play the Czech world doubles No 1 Siniakova, who has a singles ranking of No 86, in the semi-finals.

“She’s one hell of a player, really dangerous,” Boulter added. “I know what to expect and it will be down to who gets the first strike in.

“I think it’s going to be a great match and I’ve got nothing to lose again. I’m going to have to come prepared tomorrow.”

Boulter, the eighth seed in Japan, had previously reached the semi-finals of Queen’s in June while she won the title in Ostrava back in February.

The other semi-final in Osaka, which is a WTA 250 tournament, is the all-American clash between top seed Ann Li and Ashlyn Krueger.