Andy Murray reached a second successive US Open semi-final on Wednesday after Croatia's Marin Cilic squandered a set and 5-1 lead to lose their quarter-final 3-6 7-6 (7-4) 6-2 6-0.
Third seed Murray goes on to face Czech sixth seed Tomas Berdych - who had a shock win over Roger Federer this morning WA time - for a place in Sunday's final.
Wednesday's win was Murray's seventh in eight meetings with 12th-seeded Cilic, whose only victory over the Briton came in the fourth round in New York in 2009 when he raced to a straight-sets triumph.
But after twice serving for the second set, the 23-year-old Cilic's game fell to pieces, being broken in the fifth and seventh games of the third set.
Murray, the Olympic champion and Wimbledon runner-up to Federer this year, was quickly 4-0 ahead in the fourth set as Cilic, who came into the match having spent over three hours more on court than the Scot, wilted.
Murray broke three more times in the fourth set with the Croat winning just four points on his own serve.
Cilic ended the three-hour encounter having won just three more games from 5-1 ahead in the second set.
In other matches, defending champion Novak Djokovic reached his 14th successive grand slam quarter-final when Swiss 18th seed Stanislas Wawrinka was forced to retire from their last-16 match.
Serb second seed Djokovic was 6-4 6-1 3-1 ahead when Wawrinka, who had already complained of feeling unwell at the end of the third game of the third set, called it quits.
Djokovic, who was leading 2-0 overnight when the match was halted because of rain, goes on to face 2009 champion Juan Martin Del Potro, the Argentine seventh seed, who sent American Andy Roddick into retirement with a 6-7 (1-7) 7-6 (7-4) 6-2 6-4 win at Arthur Ashe Stadium.
Roddick, whose only grand slam title came at the 2003 US Open, gave an emotional statement to fans before being given a standing ovation off the court.
Djokovic has reached his sixth successive US Open quarter-final by dropping just 20 games in four rounds.
"I'm happy with my performances. I played well against a quality opponent and I wish him a quick recovery," added the Serb, who played his match in front of just a few hundred fans on the 10,000-capacity Louis Armstrong Stadium.
Djokovic's fellow Serb, eighth seed Janko Tipsarevic, fresh from a Twitter stir where he reignited the equal prize money row, reached his second successive US Open quarter-final.
Tipsarevic brushed past German 19th seed Philipp Kohlschreiber 6-3 7-6 (7-5) 6-2 and goes on to face Spanish fourth seed David Ferrer for a place in the semi-finals.
Just days after criticising the entertainment value of women's tennis, and questioning why the likes of Maria Sharapova and Serena Williams didn't play five sets, Tipsarevic played in front of just a smattering of fans on the Grandstand.