Nigel Sears: Coach's collapse was due to 'a bad piece of sushi'

At the time of Sears' collapse, Ana Ivanovic was a set up against Madison Keys but eventually lost the match

Tennis coach Nigel Sears believes his collapse at the Australian Open was caused "by a bad piece of sushi".

Sears, the coach to world number 17 Ana Ivanovic, fell while watching the Serb play in round three against Madison Keys on Rod Laver Arena on 23 January.

His son-in-law, men's world number two Andy Murray, was playing on a nearby court at the time of the incident.

"I really don't think it's likely my collapse was down to exertion," Sears, 58, told the Times.

"I know I was such big news at home, but it was a really strange one and I'm just really sorry I worried a lot of people unnecessarily.

"Frankly, now I feel a bit of a fraud."

Doctors at the Epworth Hospital in Melbourne and at his home in Sussex are still not totally sure what caused his collapse, but Sears believes it was an allergic reaction.

"I had sushi for 10 days in a row in Melbourne and was fine. But I suppose the law of averages dictates, you get one dodgy bit of raw fish in that time," he added.

Kim Sears, his daughter and Murray's wife, was heavily pregnant at the time of his collapse. She has since given birth to a baby daughter.

Murray, who went on to reach the final in Melbourne, said he would have quit the tournament if the news of Sears' health had not been positive.