Britain's Andy Murray produced one of his best performances in recent years to hold off Italian 13th seed Matteo Berrettini and win a five-set thriller in the Australian Open first round.
The 35-year-old Scot looked stunned after completing a 6-3 6-3 4-6 6-7 (7-9) 7-6 (10-6) win on Rod Laver Arena.
Murray, who thought hip surgery in 2019 would end his career, saved a match point at 5-4 in the decider.
Dan Evans is also through after beating Argentina's Facundo Bagnis.
The Englishman, seeded 25th, won 6-4 4-6 6-4 6-4 in a first-round match that was delayed for three hours because of extreme heat in Melbourne.
Former world number one Murray later ensured four Britons would play in the second round - after Emma Raducanu and Cameron Norrie won on Monday - with a memorable triumph against last year's semi-finalist Berrettini.
It was 66th-ranked Murray's first success over a top-20 opponent at a Grand Slam since 2017.
After racing 6-1 ahead in the first-to-10 final-set tie-break, Murray secured victory after almost five hours with a forehand which took a huge chunk of the net cord and left 26-year-old Berrettini stranded.
The three-time major champion will play Italian veteran Fabio Fognini or Australia's Thanasi Kokkinakis in the second round on Thursday.
"I will be feeling it this evening and tomorrow but right now I'm unbelievably happy and proud of myself," said Murray, a five-time runner-up in Melbourne.
"I've been working to give myself the opportunity to perform in matches like this and against players like Matteo. It paid off tonight.
"I was a bit lucky at the end with the net cord, but it felt like some of the tennis was really good.
"He's an unbelievable player and one of the best competitors."
Evans, 32, will play French veteran Jeremy Chardy next.
The British number two had moved into a two-sets-to-one lead when the players were taken off court as temperatures topped 35C at Melbourne Park.
Cooler conditions when they returned at 5pm local time - after a three-hour break - helped Evans wrap up the win.
Evans beat Bagnis in the first round when he reached the Melbourne last 16 in 2017 - a career-best run in MelbourneMetal-hip Murray defies the odds again
Nobody upsets the odds quite like Murray and this latest act of defiance was the greatest since he had the surgery four years ago which left him with a metal hip.
When the draw for the Australian Open pitted Murray against Berrettini, the general consensus was the veteran Scot had landed an opponent who would leave him cursing his luck.
Instead, an upbeat Murray felt playing the 2021 Wimbledon finalist was an opportunity to earn the statement win he has long craved.
Murray produced some of the best tennis he has played since his comeback, particularly in the opening two sets as Berrettini struggled to fire up his devastating forehand.
After Murray was unable to take break points for a 3-1 lead in the third, Berrettini discovered his rhythm and strong serving enable him to eventually level.
Momentum had swayed away from Murray and his energy seemingly started to dip as Berrettini continued to grow in confidence.
But the British number four's refusal to know when he is beaten came to the fore once again as he avoided losing from a two-sets lead for only the second time in 159 matches.
Costly miss on match point 'sums up' Berrettini's defeat
The pivotal moment of a gripping contest - turning it back in Murray's favour - came when Berrettini choked after being presented with a golden opportunity to win the match.
Murray poorly executed a drop-shot and, with options to beat his stranded opponent at either side, Berrettini dumped a straightforward backhand into the net.
Those watching on Laver could not hide their disbelief as a loud, collective gasp echoed around Melbourne's show court, while Berrettini clutched his face before managing a rueful smile.
"It's really tough to talk about the match now. It could have been different just with a different ball," Berrettini said.
"I had a match point. I missed on his ball. That sums up the match."
Berrettini composed himself to hold the next game, but lost his serve at the start of the tie-break when Murray showed all his quality to win the point with a backhand down the line.
That laid the platform for Murray to dominate the breaker and, after a slice of luck with the winning point, he secured his first top-20 win at a major since beating Japan's Kei Nishikori at the French Open in 2017.
Analysis
BBC tennis correspondent Russell Fuller in Melbourne
After an ice bath and a hot shower, Murray made his way wearily through the bowels of the Rod Laver Arena and into the main interview room.
He conducted his BBC radio interview en route. He said he had been nervous beforehand - usually a good sign - and practising well, which is not something he has always been able to say before a big tournament.
Murray was able to produce his very best tennis in the 10-point tie-break which decided the match. He had never played one in competition before and said he was grateful for Ivan Lendl's suggestion that they should practise them regularly in training in Florida at the end of last year.
Four hours and 49 minutes of Grand Slam tennis will deplete the reserves of anyone, of any age and any type of hip, but Murray says his pre-season work gives him the belief he can rebound strongly in the second round.
