Venus Williams continued her remarkable season by winning a superb battle against Petra Kvitova to reach the US Open semi-finals for the first time in seven years.
After final defeats at the Australian Open and Wimbledon, the 37-year-old Williams finds herself within two victories of a first grand slam title on home soil since 2001.
She was pushed all the way here in a thrilling duel, eventually prevailing 6-3 3-6 7-6 (7/2) in a deciding tie-break after two hours and 35 minutes.
Williams said: “It feels amazing. I’m so fortunate to have won that match. It came down to the wire and I hope we have more matches like that.
“I try to tell myself to enjoy the competition and enjoy the battle and I think I was able to do that tonight.”
Williams’ victory also ensures she will return to the top five in the rankings for the first time in six years, irrespective of the result of her next match against fellow countrywoman Sloane Stephens.
The pair completed half of what could be an American clean sweep of the semi-finals, with Coco Vandeweghe and Madison Keys playing their matches on Wednesday.
This was the most anticipated match of the day, with Kvitova having produced a stunning performance to defeat Garbine Muguruza in the fourth round.
The Czech insisted she would continue to play with no pressure after everything she has been through, but it did not appear that way during the first set.
Kvitova actually led 3-1 after Williams served three double faults in the third game – she served a whole game of double faults against Maria Sakkari in round three – but the American settled into her rhythm after that while her opponent struggled.
Kvitova lost five games in-a-row, hitting 16 unforced errors in the set, but she could at least take heart from her previous matches against Williams.
The pair had met five times, with Kvitova winning four of them, three from a set down.
And she made a much better start to the second set, finding her range on her thumping groundstrokes and powering 10 winners past Williams in the first three games.
Williams piled pressure on Kvitova, trying to pin the Czech on her backhand side, but she managed to serve her way out of trouble, saving five break points.
Kvitova then held comfortably to force a deciding set for the sixth time in their six meetings.
From unpromising beginnings it had become a tremendous match, and even the noisy Arthur Ashe crowd silenced their constant chatter as it reached its conclusion.
It was fitting that it came down to a deciding tie-break, but it soon became clear who was going to emerge the winner.
From 1-1, Williams reeled off five points in a row. She double-faulted on her first match point but took the second when Kvitova pulled a return wide.
