Greg Rusedski insists Andy Murray's sloppy display in the opening round of the US Open is nothing to be concerned about.
The Olympic champion was far from convincing in his 6-2 6-4 6-1 victory over Alex Bogomolov on Arthur Ashe on Monday.
The Brit made a high number of unforced errors, dropped several service games and suffered from cramp before eventually prevailing against the world No 73.
Rusedski, US Open runner-up in 1997, admitted that Murray was far from his best but insisted there was nothing to worry about and says the fact that he is winning whilst playing poorly is not a bad sign.
"There are always a bit of nerves in the opening match," Rusedski told Sky Sports. "He does not always start as well as he wants but at the end of the day he won in straight sets.
"Yes, he had a bit of cramp but nothing serious there. Everyone who is a Murray fan out there will be relieved. When you don't play well and you win, that is a great sign."
Murray had to wait to begin his US Open campaign as rain descended on Flushing Meadows and his opening match was delayed before the conditions heated up rapidly.
Sky Sports' Annabel Croft thought Murray looked uncomfortable in the humid conditions, and with the nerves of starting another hunt for a first Major title, but she says was always confident he would progress to the next round.
"I never really doubt that he is not going to get through those matches," she said. "You want to see him playing the sort of tennis that saw him getting to the final of Wimbledon and winning the Olympic gold medal, where he was really going after the ball and hitting to the corners.
"He is nervous out there and he is trying to bide his time to get the rhythm going in the match and try to feel out the conditions here. I genuinely think he really didn't feel great out there.
"It is incredibly hot and humid with that weather we had earlier, and I think that combined with the nerves can be really sapping.
"The trouble with him is that he doesn't realise what messages he is giving off with his body. So everybody around can see that he is not feeling great, it is very negative and even the opponent can pick up on things like that."
Murray will face Ivan Dodig in the next round and Rusedski is confident he will progress against the world No 118.
"Dodig is a guy with a wonderful story," said Rusedski.
"He slept rough because he could not afford to go to tournaments and he really sacrificed everything to become a tennis player because he did not have the finances to be able to do it.
"He is a guy who is determined and dogged, and going to fight hard but at the end of the day Murray just has too much class."
On Murray's slow start to the tournament, Rusdeski added: "He is not like Federer or Nadal or Djokovic, who play really well in their first match coming back from a bad spell or coming back from not playing in a long time.
"It takes him a little bit more time to acclimatise, but he is so much better than everybody in the first rounds so he can get away with it. So it is a gradual progression; you don't want to play your best tennis until the second week.
"Having won in three straight sets is a good sign and the draw on top of that is not that bad in the second round, it is more that his test will come in the third round, fourth round and quarters."