Russia's Ekaterina Makarova reached the first grand slam singles semi-final of her career with victory over two-time US Open runner-up Victoria Azarenka.
Makarova, who is also through to the semi-finals of the women's doubles with Elena Vesnina, was the more consistent player throughout and won 6-4 6-2 to finally emerge triumphant in her fifth slam quarter-final.
Azarenka lost to Serena Williams in the final for the past two years and will drop out of the top 20 as a result of this loss.
The former world number one had played by far her best tournament since returning from a persistent foot injury at Eastbourne in June.
But it had not been an easy journey and she was pushed all the way by 21-year-old qualifier Aleksandra Krunic in the previous round.
Makarova, on the other hand, went into the match having not dropped a set and upset seventh seed Eugenie Bouchard last time out.
It was a contest of fierce hitting but it was left-hander Makarova who recovered from a break down to edge the first set with a break of serve in the final game.
The Russian is the leading female player to be coached by a woman having worked with Evgenia Manyukova since 2007.
Azarenka put the pressure on early in the second set but Makarova resisted and then broke for 4-2, prompting Azarenka to destroy her racquet.
It did not help her cause, though, with Makarova ending the match on a run of four games in a row, clinching victory when Azarenka placed a forehand wide.
Makarova said: "Finally I am in the semi-finals. I had five chances and finally I'm here. It's a great feeling."
The 26-year-old is the only left-hander to beat Serena Williams at a slam and she could meet the world number one in the last four.
On being coached by Manyukova, Makarova said: "I just really enjoy to work with her. Eight years we are working together and it's getting better and better."