Britain's new women's number one Johanna Konta has failed to complete a spirited comeback against Venus Williams in the quarter-finals of the Wuhan Open.
Konta, who has leapfrogged Heather Watson into the top spot, suffered a 4-6 6-3 7-5 defeat to the 35-year-old American.
The Brit came out of the blocks firing as she pushed Williams to four break points, but the American managed to hold off the assault to keep serve.
Konta refused to give up as she managed to break serve twice, but Williams just got the better of her opponent with three breaks of her own, which sealed the first set.
Both players were stronger on serve in the second, but it was Konta who administered a crucial blow to go a break up.
A further break point for the 24-year-old was enough to square things up in China, with it all to play for in a third and final set.
Konta took the upper hand by breaking in the fourth game, but Williams, who has seven Grand Slam titles to her name, matched her opponent by immediately breaking back.
The Brit fought her way on top again to go 5-3 up, needing to serve for the match, but she crumbled as Williams converted her second break point and then held to keep herself in contention.
From that moment, it was downhill for Konta as she lost serve again, giving Williams the chance to serve for the match and a spot in the semi-finals.
It had to be hard fought by Williams as Konta created three break points and denied the American her first match point, but the five-time Wimbledon champion eventually got over the line.