Andy Murray stretches his leg between serves against Robin Haase during his opening round match at the U.S Open. He battled full-body cramps throughout the match. (Kathy Willens/AP)

Battling cramps, Andy Murray needed four grueling sets to survive his first-round match at the U.S. Open against Robin Haase , winning, 6-3, 7-6 (8-6), 1-6, 7-5, on Monday. Murray said he did not consider retiring during the match and he doesn’t know what his physical condition will be like in his next one.

“Well, cramps, it hurts. It hurts a lot,” said Murray, who will next play Matthias Bachinger on Thursday. “When it is the whole body, that’s when it — I mean, it’s not really scary, but it’s just like, you know, you don’t want to go into certain positions, because when the muscle totally goes into cramp, then it’s very, very painful. It’s very sore. So, yeah, just glad it didn’t really get to that stage where I actually couldn’t move.”

Murray grabbed at his hamstring several times in the fourth set, and after serves he would rotate his left arm. Murray, who won the U.S. Open in 2012 and Wimbledon in 2013, has had inconsistent results this year, but said on Saturday that he felt confident entering this year’s U.S. Open.

“I was very surprised when it happened,” Murray said. “Then it’s hard because you want to be able to just focus your energy on trying to win the match, but you need to then have tactics as to how you’re going to deal with how you’re feeling. You know, do you try to finish the match in three sets after I had gone a break down at the beginning of the third? Do you try and conserve energy? It becomes tricky, and you start to think about the cramps rather than just actually what you’re trying to do on the court, which is obviously win the match.But, yeah, I managed to get through in the end.”

Kyrgios emotional in win

Since his stunning upset of Rafael Nadal at Wimbledon, young Aussie Nick Kyrgios has experienced the highs of victory and the subsequent pressure of expectations. With the world suddenly watching, he split with Coach Simon Rea two weeks after making the Wimbledon quarterfinals, then he had to pull out of the Western & Southern Open because of an arm injury.

In his first-round win over Russian Mikhail Youzhny, 7-5, 7-6 (7-4), 2-6, 7-6 (7-1), the emotion boiled over before a full crowd. Kyrgios was slapped with three code violations, one for ball abuse and two for audible obscenity. He was one code violation away from getting defaulted.

“I was frustrated the way I was playing, and, yeah, it was just all that sort of stuff,” Kyrgios said. “It was just an outburst, and hopefully I will be able to control that the next time I play.”

Kyrgios said his emotional nature stems from having high expectations for himself, and it doesn’t help him on the court most of the time. Kyrgios will play Andreas Seppi in the second round.

Top seeds advance

No. 1 ranked Novak Djokovic defeated Diego Schwartzman; third-seed Stan Wawrinka swept Jiri Vesely. In the women’s bracket, fourth-ranked Agnieszka Radwanska and fifth-ranked Maria Sharapova won their first-round matches in straight sets.