Defending champion Rafael Nadal survived an epic US Open quarter-final confrontation to defeat battling ninth seed Dominic Thiem 0-6, 6-4, 7-5, 6-7 (4/7), 7-6 (7/5) and reach the semi-finals for the seventh time.
Meanwhile, six-time champion Serena Williams shook off a sluggish start to power past eighth-seeded Karolina Pliskova 6-4, 6-3 and into the semi-finals.
In a gripping 4-hour 49-minute contest which concluded at 2.04am on Wednesday, world number one Nadal won through to keep his bid for a fourth title in New York and 18th Grand Slam crown on track.
However, the 32-year-old was fortunate to triumph on another hot and humid night at Flushing Meadows, 24 hours after Roger Federer had been dumped out of the tournament by John Millman.
After suffering a first set ‘bagel’, Nadal had to battle back from breaks in the third and fourth sets before seeing off the first top 20 player he had faced at the US Open since 2013.
Nadal had defeated Thiem in the Roland Garros final in June but this was their first meeting away from a clay court.
In a dramatic final set, Nadal saw five break points come and go before Thiem went long with a smash on the first match point.
It was his 58th unforced error on a night when he sent down 18 aces and fired 74 winners.
The semi-final will pit Nadal against third seed and 2009 US Open champion Juan Martin del Potro for the second successive Grand Slam.
Del Potro reached the semi-finals for the third time, defeating John Isner 6-7 (5/7), 6-3, 7-6 (7/4), 6-2 and ending American hopes of a first men’s champion at the event since 2003.
Williams, chasing a record-equalling 24th major title, surrendered an early break to Pliskova, but she roared back with a streak of eight straight games to put away the opening set and take a 4-0 lead in the second against the woman who beat her in the semi-finals at Flushing Meadows in 2016.
Williams did indeed cut down on the errors, and came up with the big serves when she needed them.
She finished the match with 13 aces and will take on Anastasija Sevastova for a place in the final after the 19th-seeded Latvian toppled defending champion Sloane Stephens 6-2, 6-3.
World number three Stephens, refused to blame the punishing afternoon heat and humidity for her lapses against Sevastova, including an inability to convert any of seven break chances in the opening set.
Sevastova herself relies on variety more than power, and she caught a slow-moving Stephens with a number of drop shots and drop shot-lob combinations.
After taking a 4-1 lead in the second set, Sevastova admitted she had flash backs to last year’s quarter-finals, when an 83rd-ranked Stephens rallied from a break down in the third to upset Sevastova in a tiebreaker.
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