Simon Briggs Tennis Correspondent 04 March 2024 4:24pm GMT Katie Boulter has broken into the world’s top 30 after scoring the biggest triumph by a British woman since Emma Raducanu won the

US Open. In a spectacular week in San Diego, Boulter overcame five successive top-40 opponents to lift the title and confirm her position as one of the most in-form players on the WTA Tour

this season. Boulter starts the new week as the world No 27 – the highest ranked Briton of either gender. Few would have predicted this when she entered last summer’s grass-court season at

No 125, but her maiden tournament win in Nottingham last June set her on a sharp upward trajectory. Boulter was watched from the stands by her Australian boyfriend, Alex de Minaur, who had

Lleyton Hewitt and Kim Clijsters both came good in Indian Wells in 2003. Interestingly, the prize money each won highlighted the gender pay gap in tennis: De Minaur scooped $412,000, Boulter

$142,000. Boulter’s final against Marta Kostyuk started late on Sunday night, UK time, and seemed to be going against her when Kostyuk fired off a barrage of winners to claim the first set.

Both women were having trouble with their second serves, committing 10 double faults between them by this stage, but it was Boulter who looked the shakier. From that moment, though, Boulter

found a more reliable pattern from the baseline as she leaned heavily on her thunderous forehand. This shot has always been the key to her game, and she has been crushing it in San Diego

all week. “This week has been very, very special for so many different reasons,” said Boulter in her acceptance speech after a 6-7, 6-2, 6-2 victory. “This one is pretty amazing, I’ve worked

very hard for it, I played some incredible tennis all week. “Today was a complete battle, with myself as well, because I was a little bit nervous. But I managed to get over the line, and

that I’m very proud of. “A lot of it was about me staying as tough as I possibly could mentally, and I managed to keep my cool and actually kind of went within myself and calmed myself down

a lot. I think that really helped me, and then I started to relax and play through shots a little bit more.” It probably helped that Boulter had already won that title in Nottingham, even

though the two events were poles apart in quality. There, she was ranked above every one of her five opponents, with fellow Brit Jodie Burrage the pick of the bunch at No 131. In San Diego,

by contrast, she started as the underdog on paper in each match, but came through against Lesia Tsurenko (36), Beatriz Haddad Maia (13), Donna Vekic (28), Emma Navarro (26) and Kostyuk (34).

Boulter also thanked De Minaur in her victory speech, adding: “He finished last night at midnight and I really want to embarrass him. He got on a 4.15 taxi this morning and six o’clock

flight to be here today, so I do appreciate it.” A couple of minutes earlier, Kostyuk had spoken tearfully about her family, who live in the embattled Ukrainian city of Kyiv. “I don’t want

to make it sad,” she said. “I want to say thank you to my family back home, it’s been a difficult couple of nights for Ukraine, I don’t know what’s going to happen tomorrow but there is

nobody who has sacrificed more for my career than them.” Both these women are on track to be seeded at May’s French Open, which would be a first for either. Now 21, Kostyuk was a much bigger

noise than Boulter as a junior, having won the girls’ event at the Australian Open at the precociously early age of 14. Boulter is 27 and has been treading the boards already for a decade.

Her sudden blossoming is reminiscent of Johanna Konta’s unexpected breakthrough at the age of 24. Her game has evolved dramatically under the coaching of the Lawn Tennis Association’s

Biljana Veselinovic (in fact, both finalists have female coaches, as Kostyuk works with Polish guru Sandra Zaniewska), while a winter spent training with Andy Murray’s former fitness coach

Matt Little has also improved her movement. If Boulter has been a late bloomer, one explanation may lie in the chronic fatigue syndrome that restricted her to her own bed for several months

in 2015 and limited her training schedule for years after that. She also suffered a serious spinal stress fracture while representing Great Britain in a team event in 2019. The last 18

months or so represent the first time she has been able to play consistently without physical niggles, and the results have been striking. Boulter’s performances in San Diego were neatly

summed up by the 1980s legend Pam Shriver, who was at the tournament coaching Boulter’s defeated quarter-final opponent Donna Vekic. “Katie is strong on both sides, and the forehand held up

well under pressure,” Shriver told _Telegraph Sport_. “She has remained very positive on the court, including plenty of self-talk with little mantras. “I thought she played with confidence,

crushing second serve returns and closing out her matches well – as when she was brought back from 5-1 to 5-3 by Donna but still won the next game. Her court coverage is much better than it

used to be, giving her the ability to hit her way out of trouble a lot more often.” Shriver also cited Boulter’s two-year relationship with De Minaur as a beneficial influence, adding: “Alex

has been playing top-10 tennis this season, so this is not a big deal in their household or hotel room.”