Andy Murray recovered from a second-set slump to see off a spirited challenge from Portugal's Joao Sousa and move into the Australian Open fourth round.

The world number two easily took the first set but allowed Sousa back in before recomposing himself in a 6-2 3-6 6-2 6-2 win against the number 32 seed.

The 28-year-old Briton will next play Australia's Bernard Tomic, seeded 16th.

As Murray was on court, news broke of his father-in-law Nigel Sears collapsing in the Rod Laver Arena.

Sears coaches Ana Ivanovic and was watching her match against Madison Keys. Murray's brother Jamie told reporters that the 58-year-old, who has been taken to hospital for tests, was "conscious, talking and sitting up".

Sears' daughter Kim is not in Melbourne in support of her husband Murray as she awaits the birth of their first child in a few weeks.