Great Britain’s Katie Boulter stunned American world number five Jessica Pegula for the biggest win of her career at the United Cup in Perth.
Boulter, ranked 51 places below Pegula, came from a set and double break down to win 5-7 6-4 6-4 and put GB ahead.
It marked the 27-year-old’s first victory over a top-five opponent.
Team-mate Cameron Norrie then lost to Taylor Fritz to send the best-of-three tie to the deciding doubles, where Boulter and Pegula will meet again.
Fritz beat Norrie 7-6 (7-5) 6-4 and will team up with Pegula to face Boulter and Neal Skupski. Should Great Britain win, they 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.
In the second singles match, world number 18 Norrie got off to a slow start as Fritz – ranked eight places higher – raced into a 4-1 lead.
Although the Briton levelled at 5-5, it was Fritz who edged a tight tie-break to win the first set, before the American got the decisive break of serve in the ninth game of the second set to send the tie to deciding mixed doubles.
