Eighth seed Andy Murray needed more than three hours to win his opening match against Dutchman Robin Haase at the US Open here after complaining of cramps.
The 2012 US Open champion came up with cramps all over the body during the match and that made it much tougher for Murray than it was expected Monday night, reports Xinhua.
The world number nine beat Haase 6-3, 7-6 (6), 1-6, 7-5 to earn a second round berth.
"It was tough, very unexpected," said Murray who claimed he felt good physically the day before, "especially after an hour and a half".
"Normally it's kind of a gradual thing, but after maybe two hours and a half, three hours."
Murray played a defensive match because of the cramps. He made 15 winners, far behind Haase's 61, but the 52 unforced errors, 40 more than Murray, cost the 27-year-old Dutchman dear.
Murray will encounter Matthias Bachinger from Germany in the round-of-64 match.