Johanna Konta is out of the Western & Southern Open in Cincinnati after losing her quarter-final against second seed Simona Halep 6-4 7-6 (7/1) on Friday night.
Seventh seed Konta, who beat Halep in the quarter-finals at Wimbledon in July, did not go quietly, saving a series of match points and keeping Halep on court for almost two hours.
Konta, who had not lost to the Romanian in three previous meetings, saved two match points when trailing 5-3, and was down 40-0 down at 6-5 before battling back to win the game.
But Sky Bet's 6/4 favourite Halep regrouped and romped through the tiebreaker to set up a semi-final against 13/2 shot Sloane Stephens.
In delayed third-round action, held over from a wet Thursday, Czech world number one Karolina Pliskova (15/8) beat Italian qualifier Camila Giorgi 6-3 4-6 6-0, Stephens saw off Russia Ekaterina Makarova 2-6 6-3 6-4, and Germany's Julia Goerges was a 7-5 6-4 winner against Ukrainian Elina Svitolina.
Wimbledon champion and 3/1 shot Garbine Muguruza clinched a semi-final berth after a mighty contest against Svetlana Kuznetsova.
The Spaniard won through 6-2 5-7 7-5 against her Russian opponent, just a day after a similarly gruelling test against American Madison Keys.
Victory was secured when a powerfully-struck deep forehand from Muguruza was followed by Kuznetsova returning the ball into the net.
Muguruza is an 11/8 shot to beat Pliskova and reach the final.