Heather Watson has declared that a medical timeout in the second set provided the respite she needed to claim a spirited comeback win on day one of the Australian Open.

The British number one was down a set and a break to Romanian Alexandra Cadantu before taking a timeout to have her temperature and pulse checked in the Melbourne heat.

Despite suffering from cramp in the closing stages, Watson produced a stirring fightback to beat Catantu in three sets and claim a place in the second round.

Watson has admitted that she will need to visit a doctor later today but is relieved to have come through a difficult test.

She told reporters: "At the beginning I definitely wasn't there. I wasn't playing well, I didn't have much energy today.

"I don't know what it was. I think I'm going to see the doctor. When I started cramping, I had to start hitting the ball because I couldn't move.

"I'm kind of thankful that I did cramp today, otherwise I don't know how that would have ended up. I think the break did help me. It gave me time to eat, get some fuel in me and just get recharged."

Left-hander Ksenia Pervak awaits the Brit in round two.