Greg Rusedski expects Andy Murray to go deep in the US Open despite suffering cramp problems in his 6-3 7-6 (6) 1-6 7-5 victory over Robin Haase.
Murray, the 2012 champion, struggled with cramps in his legs and arms as the Dutchman breezed through the third set but recovered to close out the match in the fourth.
The Briton – who will play German qualifier Matthias Bachinger in the second round – attributed the scare to his diet, saying: "The fact that it was the whole body would suggest that maybe it was something to do with my eating or drinking, because if it's through fatigue in one part of your body, then that would probably be down to conditioning.
“But cramping in my left forearm? I didn't use my left forearm a whole lot today compared with other parts of my body, so I would expect it would be something to do with what I have eaten or not eaten."
But Rusedski reported that there is a theory that Murray’s cramping could be caused by nerves.
“Richard Evans, one of the journalists, was talking about Bill Norris – who is an ATP trainer out there – and he said ‘look, I’ve never seen anyone cramp in practice and Murray practices harder than anybody out there’.
“But he says that usually the cramping is caused by nervous energy – when you are really stressed by things out there. So I think that maybe it is the expectation because he hasn’t been to a finals this year or won a tournament since he won Wimbledon.
“It could be a combination of a few different things. Maybe he’ll now relax a little bit more into these Championships and start playing a little bit better, because it’s very odd for him with all of the experience on his team.
“Let’s hope this is just a little hiccup and we get back to the Murray of old. I’m still feeling positive about it. I think he will come through and that he is going to progress well in this tournament. You have one blip match and this was it.”
But fellow Sky Sports pundit Annabel Croft suggested that Murray - if anything - should feel under less pressure to perform in these Championships.
“It’s interesting that he would feel more stress, if that’s the case as to why he has cramp, because actually I’ve been looking at him coming into these Championships thinking in the past we’ve always had such high expectations of him.
“This is the least pressure that I would say he’s had on him coming into a Slam for a very, very long time because he’s down at eight in the seedings – and he could have been outside of that if Nadal had been here.
“In many ways it is a nice position for Andy because in the past we’ve expected an awful lot of him and there is less expectation on him this time.”
Our US Open coverage – which today includes both Roger Federer and Serena Williams - continues from 4pm on Sky Sports 4. For news, interviews and analysis visit www.skysports.com/tennis