Andy Murray would have pulled out of the Australian Open had there been any doubts about the health of his father-in-law Nigel Sears.

Sears collapsed on Rod Laver Arena on Saturday while he watched Ana Ivanovic, whom he coaches, and was rushed straight to a Melbourne hospital.

Murray visited Sears twice, on Saturday night and Sunday morning, before the 58-year-old was released and given the all clear to fly home.

The British number one recovered his focus to beat Australia's Bernard Tomic 6-4 6-4 7-6 (7/4) on Monday but said he would not have played if the news on Sears had been less positive.

"It was tough, obviously it depended on Nigel's health," Murray said.

"If the news was not positive then no there was absolutely no chance I would have kept playing.

"It was a tough few days. It certainly wasn't straightforward. I'm just glad that he's on his way home now and can be back with his family."

Murray has been busy with off-court issues throughout his time in Australia, with his wife Kim heavily pregnant and expected to give birth in the middle of February.

Sears' illness, however, was as concerning as it was unexpected for the 28-year-old, who admits he carried his anxiety into the match against Tomic.

"Today when I woke up I felt quite drained, quite tired," Murray said.

"As the day went on and I decided to play, I started to focus a little bit better but definitely on the court tonight I was more emotional than normal.

"I was talking to myself after every single point almost from the first point through to the last, which was obviously not ideal.

"That uses up a lot of energy. Again, just that makes you sort of more kind of up and down throughout the match, as well.

"Certainly I was trying to just concentrate on the match when I was out there but like I said, it's been a hard, hard few days.

"Hopefully it gets better in the next few days. I just can't believe something like that happened a few days ago. It's shocking. Nige is an unbelievably fit guy. Very, very scary."

Murray was certainly not at his rhythmic best against Tomic, who broke the Briton four times during a topsy-turvy contest.

The world number two, however, delivered at the crucial moments to secure a quarter-final meeting with Spain's eighth seed David Ferrer.

"I didn't think it was that straightforward. It was a tricky match," Murray said.

"I got up a break I think in all of the sets. Each time he obviously got it back. So there were quite a few momentum shifts in all of the sets.

"Luckily he missed a few easy forehands in the tie-break, and that helped me out in the breaker. It helped me get it done in straight sets."