Andy Murray conjured old magic in a five-set thriller to dump last year's semi-finalist Matteo Berrettini out of the Australian Open on Tuesday as scorching heat gave way to driving rain in a day of manic weather at Melbourne Park.
Former world number two Alexander Zverev nearly lost his head in the maelstrom as he laboured against Peruvian lucky loser Juan Pablo Varillas before winning another five-setter to join Murray in the second round.
More than 20 matches were suspended over the cause of day two, with the first tranche halted three hours into the day session due to extreme heat.
As night fell, a storm brought a cool change and heavy rain, leaving the action confined to the roofed showcourts ahead of nine-times champion Novak Djokovic's first round clash against Roberto Carballes Baena.
Coming off a big pre-season, Murray channelled his halcyon days of 2016 as he raced to a two-set lead then saw off a brave fightback from 13th seed Berrettini in a 6-3, 6-3, 4-6, 6-7(7), 7-6, (10-6) slog that lasted nearly five hours.
Beaten by the hard-hitting Italian at the U.S. Open, Murray saved a match point then sealed his own with outrageous fortune, a return clipping the net cord in a cruel finish for Berrettini at Rod Laver Arena.
"I just got a bit lucky there at the end with the net cord," said 35-year-old Murray, a five-times finalist at Melbourne Park.
"Right now I'm just unbelievably happy, just proud of myself."
Twelfth seed and former semi-finalist Zverev had a huge scare against world number 103 Varillas but the German steadied to win a four-hour dogfight 4-6, 6-1, 5-7, 7-6(3), 6-4 at Margaret Court Arena.
It was the German's first win since June, having torn ligaments in his right foot in the French Open semi-final against Rafa Nadal.
Top 10 men's seeds Andrey Rublev and Taylor Fritz eased into the second round earlier in the day.
Russian Rublev beat former finalist Dominic Thiem 6-3 6-4 6-2 as temperatures nudged 36 degrees Celsius.
"It's super hot today so I'm super happy I was able to win in straight sets and save some energy for the next match," the fifth seed said.
"The hotter it is, the tougher it is to make the right decisions, the tougher to move."
Fritz followed Rublev onto the John Cain Arena and, with closed roofs keeping play going on the three main showcourts, he outlasted tricky Georgian Nikoloz Basilashvili 6-4, 6-2, 4-6, 7-5.
Women's seeds Aryna Sabalenka and Caroline Garcia enjoyed the relative cool earlier in the day on Rod Laver Arena.
Fifth seed Sabalenka, who opened the year by winning the Adelaide title without losing a set, kept up her fine form with an emphatic 6-1, 6-4 victory over Tereza Martincova.
Fourth seed Garcia, who won the WTA Finals last season, was equally convincing with a 6-3, 6-0 win over Canadian qualifier Katherine Sebov.
Garcia will face another Canadian in 2021 US Open finalist Leylah Fernandez, who beat Alize Cornet 7-5, 6-2, her first win in the main draw at Melbourne Park.
Rublev and Sabalenka, like all Russian and Belarusian players, are competing at the tournament without national affiliation as a result of last year's invasion of Ukraine.
Tennis Australia on Tuesday morning banned fans from bringing flags of either nation into the Melbourne Park precinct after a Russian tricolour was hung on a bush next to a court where Ukrainian Kateryna Baindl was playing on Monday.
"I really thought that sport is nothing to do with politics but if everyone feels better this way,