Serena Williams came from behind to progress to the US Open semi-finals with a hard-fought three-set victory over Tsvetana Pironkova.
After battling her way past Maria Sakkari, Williams overcame another tricky opponent in Pironkova, who astonishingly reached the quarter-finals in what was the Bulgarian's first tournament for three years following the birth of her son.
The six-time US Open champion took the match 4-6, 6-3, 6-2 to continue her march towards a 24th Grand Slam title, which would see the American draw level with Margaret Court's long-standing record.
Williams will next face either Victoria Azarenka or Elise Mertens, who play later tonight, for a place in what would be her third successive US Open Final at Flushing Meadows.
Though Williams entered the match with a 4-0 head-to-head lead, it was Pironkova who drew first blood, with a sumptuous backhand winner down the line ensuring an early break of serve in the fifth game.
Williams saved two set points in the ninth game to force Pironkova to close it out on her serve, which the 32-year-old accomplished without hesitation, whipping yet another backhand winner cross-court to hold to love.
Pironkova carried the momentum into the second set and moved further ahead by breaking Williams in the opening game, with the American struggling to acclimatise to the unorthodox forehand slice repeatedly coming her way.
A fired-up Williams showed Championship steel just when required, however, breaking back the following game, before serving out the set after prevailing in a mesmerising 26-shot rally to break once more in the game prior.
It was Williams who then made the fast start in the deciding set, breaking in the opening game to take the lead for the first time since the third game of the match.
The third seed - making her 20th appearance in New York - broke once more in the seventh game, before sealing the match with a hold to love.
Williams - who is now in her fourth week within the bio-secure bubble at Flushing Meadows - faces a quick turnaround before playing again on Thursday evening.