Boulter entered the match knowing that reaching the semi-finals would be sufficient to overturn the 55-point deficit that had seen her briefly overtaken by Sonay Kartal earlier in the week. Kartal had moved ahead in the rankings following her recent run to the final in Wuhan.

The match against the 91st-ranked Ruzic proved a stern test for the eighth seed. Boulter trailed by a set and a break before mounting a successful recovery, eventually securing a 3-6, 6-3, 6-3 victory after two hours of play.

This result marks Boulter’s first appearance in a semi-final since the tournament at Queen’s Club in June. She is now scheduled to face Katerina Siniakova for a place in the final, with the ranking update on Monday confirming her return to the world's top 50.

Reflecting on the contest, Boulter praised her opponent's performance. She noted that she had to remain patient and find a way to stay in the match despite the difficult start, acknowledging that she received a bit of luck during the second set.

Looking ahead to her semi-final clash with Siniakova, Boulter expressed caution regarding the challenge ahead. She described the Czech player as an extremely dangerous opponent and emphasised the importance of being prepared for the opening exchanges of the match.

Boulter’s performance on serve was inconsistent during the early stages of the encounter. She won only 60% of points behind her first serve and committed four double faults, while also facing seven break points throughout the opening two sets.

The match began poorly for the Briton, who was broken in her opening service game. Although she managed to claw back a break at 4-2 when Ruzic double-faulted, the Croatian responded immediately by winning the next four games to claim the set.

The second set proved to be a scrappy affair, but Boulter managed to regain control. She saved two break points in the third game to prevent falling behind by a double-break and secured a vital hold in the seventh game.

That hold of serve proved to be a turning point, initiating a sequence where Boulter won eight consecutive games. This surge allowed her to establish a commanding 4-0 lead in the deciding set, effectively shifting the momentum of the match.

Although she faltered slightly when attempting to serve out the match at 5-2, Boulter responded by breaking her opponent to love in the following game. This final break confirmed her victory and her progression in the tournament.

The battle for the British number one spot has become a significant subplot as the 2026 season draws to a close. While Kartal enjoyed a breakthrough week in Wuhan, Boulter’s continued consistency has allowed her to reclaim the top position.

Boulter is expected to have further opportunities to consolidate her ranking in the coming weeks. She is scheduled to participate in upcoming events in Tokyo and Hong Kong, which could see her climb further up the world rankings.

In contrast, Kartal’s schedule for the remainder of the season remains uncertain as she manages her physical workload. The competition between the two players is expected to continue into the start of the 2027 season.

Emma Raducanu also remains a factor in the British rankings, though her participation for the remainder of the year is in doubt. She has been sidelined by a shin injury that previously ruled her out of Wimbledon, though she remains a top-50 contender.

Both Boulter and Raducanu have previously stated that they are not overly focused on the British number one ranking. Instead, they have maintained that their primary objective is to focus on their individual development and their progress within the global rankings.

Despite these public comments, the opportunity to finish the year as the nation's highest-ranked player provides an additional incentive for Boulter. Her performance in Osaka demonstrates her commitment to ending the 2026 campaign on a high note.

The Japan Open continues to be a key event for players looking to secure vital ranking points before the year-end break. With the field for the WTA Finals already determined, players are now focused on building momentum for the next season.

Boulter’s ability to recover from a set down highlights the progress she has made this year. Her focus now shifts entirely to her semi-final against Siniakova, where she will aim to reach her first final in several months.

As the season enters its final phase, the rivalry between Britain's top female players continues to provide intrigue. With several tournaments still to be played, the rankings are likely to remain fluid as the players compete for position.