Staff Reporter.
Katie Boulter stunned world number five Jessica Pegula for the biggest win of her career to give Great Britain a 1-0 lead over the United States at the United Cup in Perth.
Boulter, ranked 51 places below Pegula, came back from a set and a double break down to win 5-7 6-4 6-4.
It marks the 27-year-old’s first victory over a top-five opponent.
If her team-mate Cameron Norrie beats Taylor Fritz, GB will qualify for the quarter-finals of the tournament.
In January 2023, the first edition of the mixed-team competition, Pegula led the US to the United Cup title, but on Sunday she was forced to save three Boulter set points at 4-5 in the opening set.
From there, the 29-year-old won six successive games to take the first set and build a double-break advantage in the second.
But Boulter fought back, winning six of the next seven games to level the match at a set apiece, before wrapping up victory in two hours and 44 minutes.
Her previous best wins by ranking were her two victories over then-world number seven Karolina Pliskova in 2022, first at Eastbourne and then Wimbledon.