Andy Murray has admitted that he was "not particularly comfortable" in his opening match at the US Open earlier this evening.
The 2012 champion struggled with pain in his legs and arms during his four-sets win over Robin Haase at Flushing Meadows.
The Scot told BBC Sport: "I started cramping at the beginning of the third set, at the front of my quad and then in my forearm.
"It was not particularly comfortable and I just tried to hang around as long as possible and managed to get through.
"I was in a good position at 2-0 up but I didn't know whether to go for it at the beginning of the third set or conserve energy and go for it in the fourth. It wasn't easy for Robin either."
Murray faces Germany's Matthias Bachinger in the second round later this week.
