Former world number one Andy Murray survived a match point on Tuesday as he battled for nearly five hours over five sets to beat the 13th seed Matteo Berrettini.
The first round match on Rod Laver Arena ended 6-3, 6-3, 4-6, 6-7, 7-6.
Murray's brush with elimination came when he was serving to level at 5-5 in the decider.
A poorly executed drop shot gave Berrettini the chance to claim the point and the encounter.
But with the right hand side of the court gaping, the 26-year-old Italian put his backhand cross-court drive into the net.
As much astonished as relieved, Murray eventually held for 5-5. Neither man faltered in their next service game but in the final set "super tiebreaker" to 10 points, Murray opened up a 5-0 lead.
Though Berrettini chipped away at the advantage, Murray held his nerve to take the shootout 10 points to six.
Challenge
"I'm just unbelievably happy, very proud of myself," said 35-year-old Murray who contemplated retiring from the sport in 2019 following a first round loss a year after his first hip operation.
Murray decided to continue playing after a metal hip was inserted during a second operation.
"I put a lot of work into the last few months with my team, who are here, to give me the opportunity to perform on stadiums like this and matches like this against players like Matteo, and it paid off tonight."
The match took place under the stadium roof as organisers halted play on other courts for three hours due to temperatures rising to 36 degrees celsius.
Weather
Several other matches were suspended during the evening due to rain.
In matches that were completed, the 2020 finalist Dominic Thiem lost in straight sets to the fifth seed Andrey Rublev.
Ninth seed Holger Rune advanced as well as 12th seed Alexander Zverev who was competing in his first Grand Slam tournament since injuring his right ankle during the 2022 semi-final at the French Open.
In the women's draw, the 2020 finalist Garbine Muguruza went out in three sets to Elise Mertens while the fourth seed Caroline Garcia dispatched Katherine Sebov 6-3, 6-0.
The 29-year-old Frenchwoman, who claimed the women's season-ending championships in November, is among the favourites for the title.
Garcia's compatriots, Alizé Cornet and Diane Parry, fared less well. Leylah Fernandez beat Cornet 7-5, 6-2 while Taylor Townsend battered Parry 6-1, 6-1.
However, the French veteran Jérémy Chardy came from a set down to see off Daniel Galan in four sets and Benjamin Bonzi emulated his compatriot with victory in similar fashion over the Italian qualifier Mattia Bellucci from Italy.
