Australian-born Johanna Konta became only the second British woman in 24 years to reach the fourth round of the US Open by downing German 18th seed Andrea Petkovic.
Konta beat Petkovic 7-6 (7-2) 6-3 to book a last-16 matchup with Petra Kvitova, who routed Slovakia’s Anna Karolina Schmiedlova 6-2 6-1.
After almost two hours, the world No.97 qualifier reached the fourth round for the first time at any grand slam event.
It was her 16th win in a row, although many of those were in sub-WTA level events and three came in Open qualifying.
“I’m just happy to win it,” Konta said. “It was definitely tough.”
Konta joined Laura Robson from 2012 as the only British women to make the fourth round on the New York hardcourts since Jo Durie in 1991.
No British woman has reached the US Open final since Virginia Wade defeated Billie Jean King in the 1968 final.
But Konta, who became a British citizen in 2012, has one more less amazing feat within reach.
With another triumph, she would match American Barbara Gerken’s 1981 quarter-final run as the best in US Open history by a women’s qualifier.
Konta dominated the first-set tiebreaker and rolled to a 3-0 lead in the second set before Petkovic took a medical timeout for cooling and treatment for fatigue in the withering heat.
Revived, Petkovic swung momentum her way in a 10-minute seventh game, saving three match points and breaking on her fifth chance to pull within 5-2.
Konta squandered her fourth and fifth match points on her serve in the ninth game before breaking through on her sixth opportunity when Petkovic sent a forehand long.
The winner of her match with Kvitova will face the winner of the round of 16 clash between Australia’s Sam Stosur and Italy’s Flavia Pennetta.
The two tour veterans both taking three sets to get through their third round encounters – Pennetta beating Czech Petra Cetkovska 1-6 6-1 6-4 and Stosur surviving a scare against Sara Errani to win 7-5 2-6 6-1.
The win propels Stosur to the second week in New York for the first time since he was defending champion in 2012.
Two other well-credentialled women had to battle hard to make the fourth round.
Two-time Australian Open champion Victoria Azarenka defeated German 11th seed Angelique Kerber 7-5 2-6 6-4 in just under three hours and will face Varvara Lepchenko in the fourth round.
And 2013 Wimbledon finalist Sabine Lisicki came back from a double break down in the final set of her third round match to defeat Czech Barbora Strycova 6-4 4-6 7-5.
Lisicki reeling off six straight games to win the match in an epic comeback, which saw her hit 15 winners to two in the final set.
The ecstatic German collapsing to the court in triumph post match.
Lisicki will now play world No.2 Simona Halep, who brushed aside American Shelby Rogers 6-2 6-3.
Neither lady has ever made it past the fourth round at Flushing Meadows.