US Open 2017: Alexander Zverev beaten in four sets by Borna Coric
|Venue: Flushing Meadows, New York Dates: 28 Aug-10 Sept|
|BBC coverage: Live radio and text commentary on selected matches every day.|
Fourth seed Alexander Zverev has been knocked out of the US Open in four sets by Croatia's Borna Coric in New York.
The German, 20, took the first set but eventually fell to a 3-6 7-5 7-6 (7-1) 7-6 (7-4) defeat on Grandstand Court.
He had three set points in the 12th game of the fourth set to take it into a decider but Coric saved them all and sealed victory in the tie-break.
Despite winning five titles this year, Zverev has still not progressed beyond the last 16 of a Grand Slam.
"It's upsetting because the draw is pretty open in the bottom part - I felt like I should have been the favourite there. I just played a very, very bad match, that's just the way it is," he said.
"I've been dealing with expectations from a very young age, so for me this is just another step.
"I know that I could have done some big things here, something that I haven't done before, but I won't. It's as simple as that."
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Elsewhere at Flushing Meadows, Grigor Dimitrov made an assured start to his US Open with a 6-1 6-4 6-2 win over Czech qualifier Vaclav Safranek.
Austria's Dominic Thiem beat Alex de Minaur 6-4 6-1 6-1 and faces American Taylor Fritz, 20, in the second round.
Seeds Gilles Muller, Albert Ramos-Vinolas, Fabio Fognini and Richard Gasquet were all knocked out on day three at Flushing Meadows.
Wimbledon quarter-finalist Muller, seeded 19th, lost 6-7 (4-7) 6-3 7-6 (6-4) 6-3 to Italian Paolo Lorenzi.
Ramos-Vinolas, seeded 20th, lost in five sets to 35-year-old Nicolas Mahut, who won 4-6 6-4 4-6 6-3 6-0.
Fognini, the 22nd seed, was knocked out by fellow Italian Stefano Travaglia 6-4 7-6 (10-8) 3-6 6-0.
French 26th seed Gasquet, who reached the US Open semi-finals in 2013, lost 3-6 6-2 6-4 6-2 to world number 59 Leonardo Mayer.
Wimbledon finalist and fifth seed Marin Cilic beat Florian Mayer 6-3 6-3 6-3, Czech 15th seed Tomas Berdych defeated American Ryan Harrison 6-4 6-2 7-6 (7-4) and Juan Martin del Potro, seeded 24th, beat Swiss Henri Laaksonen 6-4 7-6 (7-3) 7-6 (7-5).
John Isner beat South Korea's Hyeon Chung in straight sets and David Goffin overcame Julien Benneteau in four sets.
Gael Monfils saw off fellow Frenchman Jeremy Chardy 7-6 (8-6) 6-3 6-4 to set up a second-round meeting with Donald Young, while Lucas Pouille beat United States' Jared Donaldson in five.
Ukrainian Alexandr Dolgopolov, whose defeat by world number 114 Thiago Monteiro earlier this month is being investigated by the sport's integrity unit, beat Germany's Jan-Lennard Struff.
Japan's Taro Daniel will face world number one Rafael Nadal in day four's night session after emerging victorious in a five-set match with American Tommy Paul.
Uruguay's 27th seed Pablo Cuevas was beaten 7-5 7-6 (7-3) 6-1 by Bosnia's Damir Dzumhur.
BBC tennis correspondent Russell Fuller
The bottom half of the men's draw is an oasis of even greater opportunity after the events of Wednesday. Marin Cilic and John Isner are the only members of the world's top 15 who remain after the defeats of Alex Zverev and Jo-Wilfried Tsonga.
Kyle Edmund will be relishing the chance, even though he knows only too well the dangers poised by the brilliant 18 year old Denis Shapovalov, who beat him at Queen's Club in June.
Youth still has much to do to sear its mark. If the seedings go to plan, the quarter-finals in the bottom half of the draw will pit Isner against Kevin Anderson and Cilic against Pablo Carreno Busta.