Norway's Casper Ruud says he "probably won't be here the next day" if his wife goes into labour during the Australian Open.
Maria is heavily pregnant with their first child, a daughter.
Ruud, the 12th seed, beat Italy's Mattia Bellucci 6-1 6-2 6-4 in the first round in Melbourne on Monday.
"I have to thank Maria for letting me go in the first place. I know she's at home resting, getting ready," he said.
"Except for when I'm playing a match, the ringer is on all hours of the day just in case.