Two-time champion Rafael Nadal survived a scare at the hands of Croatian teenager Borna Coric to reach the US Open second round.
Nadal, who won his second New York title on his last appearance in 2013 before injury forced him to sit out 2014, prevailed 6-3, 6-2, 4-6, 6-4 against his 18-year-old opponent.
Eighth seed Nadal, the holder of 14 majors, goes on to face Argentina's Diego Schwartzman for a spot in the last 32.
Nadal blamed dehydration on a steamy, humid night in New York for his third set blip.
"I was sweating a lot. I had a little bit of a stomach problem so I didn't feel perfect, physically perfect then," said the Spaniard.
"But then in the fourth I recovered little bit. I played again more aggressive."
Coric, the youngest player in the top 50, had won the junior title in New York in 2013 when Nadal was taking the senior event.
On Monday, the world number 33 showed flashes of the talent which helped him to a shock win over the former world number one in Basel last October.
But Nadal, playing at his lowest seeding since 2004, steadied the ship with a crucial break in the seventh game of the fourth set to lay the foundation for victory.
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