Bianca Andreescu recovered from a set down to defeat Elise Mertens 3-6 6-2 6-3 and extend her superb US Open run into the semi-finals.
Mertens had not dropped a set en route to the last eight and there were ominous signs for Andreescu when the Belgian 25th seed survived early pressure on her serve and went on to take the first set on Wednesday.
Andreescu – unbeaten since the French Open – progressed to the quarters with a frenetic three-set win over Taylor Townsend in front of a late night New York crowd.
There were considerably more fans inside Arthur Ashe Stadium for this encounter, but it still had the feel of a more low-key affair. Andreescu, 19, found a spark in the second set, though, and controlled the contest thereafter.
Mertens, a member of three-time US Open champion Kim Clijsters’ academy, proved extremely resolute as Andreescu piled on the pressure.
She saved six break points in the decider but her resistance was finally shattered as Andreescu claimed a win in two hours, two minutes – booking her place in a first career grand slam semi-final, in which she will face Belinda Bencic.
Believe it, Bianca
— US Open Tennis (@usopen) September 5, 2019
Mertens staved off a pair of break points in the opening game of the match and was clinical when she received her first opportunity, converting it when Andreescu failed to properly connect with a backhand volley.
Andreescu was able to avoid going down a double break despite Mertens bringing up four more break points three games later, but she failed to find a way back into set, which her 23-year-old opponent served out to love.
Canadian Andreescu – winner of the Rogers Cup and Indian Wells this year – wasted an opportunity to impose her will on the second set as she gave an early break straight back with a backhand error.
However, she produced a magnificent sixth game to take command of the second, a backhand pass, a delicate drop shot and a rasping forehand winner giving her a 4-2 lead.
A crosscourt winner sealed the double break and forced a decider in which Mertens proved exceedingly obdurate.
It took until the eighth game for Andreescu to finally puncture Mertens’ defences, a marvellous backhand return providing what proved the decisive breakthrough.
Bianca Andreescu  bt Elise Mertens  3-6 6-2 6-3
Andreescu – 40/33
Mertens – 22/27
Andreescu – 2/3
Mertens – 3/3
BREAK POINTS WON
Andreescu – 4/16
Mertens – 2/6
FIRST SERVE PERCENTAGE
Andreescu – 62
Mertens – 64
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Andreescu – 75/50
Mertens – 60/53
Andreescu – 86
Mertens – 75