Novak Djokovic Photo: Photosport
Defending Australian Open champion Novak Djokovic said it was like "playing myself in the mirror" after he came through the longest first-round Grand Slam match of his career against teenage qualifier Dino Prizmic.
Earlier, Aryna Sabalenka started her women's title defence in dominant fashion with a rapid victory over Germany's Ella Seidel.
Djokovic, chasing a record-extending 11th men's title in Melbourne, needed four hours and one minute to beat the 18-year-old 6-2 6-7 (5-7) 6-3 6-4.
Croat Prizmic, facing his childhood idol on his debut appearance at a Grand Slam, saved six match points before Djokovic, 36, secured victory.
"[He has] so much potential. He has everything that he needs and can still improve," world number one Djokovic said of his opponent, ranked 178th.
"The way he is mentally present on the court, I like it a lot. He never gives up.
"I felt like I was playing [against] myself in the mirror. He has no weaknesses, really."
Djokovic, who could achieve a record 25th Grand Slam singles title this month, later said he had felt "under the weather".
While the Serb will face Alexei Popyrin or Marc Polmans in the second round, Prizmic - crowned French Open boys' champion last year - has a bright future ahead on the evidence of his breakthrough performance on Rod Laver Arena.
Sunday's match surpassed Djokovic's previous longest in the first round of a major, which was a three-hour-57-minute encounter against Gael Monfils at the US Open in 2005.
Few could have anticipated the absorbing tussle which would develop after Djokovic took a straightforward first set.
But Prizmic hinted at what was to come when he broke Djokovic for the first time for a 3-1 lead in the second, before holding his nerve in the tie-break with his fourth set point.
That set up a rollercoaster third set, which Djokovic claimed by winning four successive games - but only after Prizmic had battled back with a double break from 2-0 down.
And even as the result began to appear a formality in the fourth set when Djokovic continued his run of games for a 4-0 lead, his teenage opponent refused to go quietly, breaking back before saving four match points in the ninth game to force the top seed to serve out victory.
"He deserves all the applause. He is an amazing player, he handled himself incredibly well on the court. This is his moment," Djokovic said.
"It could easily have been his match as well. He showed great mentality and resilience.
"I certainly want to be in his corner. So hopefully he will invite me, because he will make some big things in his career that's for sure."
Fifth seed Andrey Rublev was "completely panicking" but survived a comeback from world number 78 Thiago Seyboth Wild to edge a five-set thriller.
The 26-year-old Russian, who will aim to reach his first major semi-final in 2024, won 7-5 6-4 3-6 4-6 7-6 (10-6) to set up a second-round meeting with Japan's Taro Daniel or American Christopher Eubanks.
Rublev has at times struggled to contain his emotions on court. Against Carlos Alcaraz at the ATP Finals in November he hit himself so hard with his racquet that he drew blood.
Elsewhere, former semi-finalist Matteo Berrettini withdrew before his first-round match against Stefanos Tsitsipas because of a foot injury, meaning the Greek seventh seed will instead play Belgian Zizou Bergs.
American 12th seed Taylor Fritz also had to come through a five-set opener, fighting back from two-sets-to-one down to beat Argentine Facundo Diaz Acosta 4-6 6-3 3-6 6-2 6-4.
Compatriot Frances Tiafoe, seeded 17th, also progressed by beating Croat Borna Coric 6-3 7-6 (9-7) 2-6 6-3.
Croatia's 2018 runner-up Marin Cilic lost 6-1 2-6 6-2 7-5 to Hungarian Fabian Marozsan.
Sabalenka comfortable
World number two Sabalenka overpowered 18-year-old qualifier Seidel 6-0 6-1 in a ruthless 53 minutes.
Aryna Sabalenka reacts to a point Photo: PHOTOSPORT
She had the chance to win without dropping a game, missing two match points at 5-0 in the second before serving out the match in the next game.
She is joined in the second round by Greek eighth seed Maria Sakkari.
Sakkari's 6-4 6-1 victory over Japan's Nao Hibino was her first Grand Slam win in a year.
"It was a difficult match emotionally but I'm happy," said the 28-year-old, who went out in the first round of the last three Grand Slams.
Elsewhere, Danish wildcard and 2018 Australian Open winner Caroline Wozniacki advanced to the second round after Polish 20th seed Magda Linette retired with injury.
Former world number one Wozniacki, appearing at the Melbourne Grand Slam for the first time since coming out of retirement last year, led Linette 5-2 in the opening set when the 31-year-old took a medical timeout and returned with strapping on her leg.
Clearly in discomfort, she attempted to continue but lost the opening set before Wozniacki ruthlessly broke in the first game of the second and Linette called time on her Australian Open campaign at 6-2 2-0 down.
Second seed Sabalenka, 25, seemed to be in no mood to make it a later night than necessary as she took immediate charge against the world number 173.
She raced to a 5-0 lead in the opening set and wrapped it up in just 22 minutes with a couple of backhand volleys at the net.
The dominance continued into the second set and it looked as though Seidel would not get on the board at all until the German saved two match points and held serve for the first time, earning huge cheers from the crowd.
Sabalenka squandered four more match points in the next game before regaining focus to seal the win.
"I still have to work hard and work for my dreams," Sabalenka said.
"It's amazing I was able to achieve so many goals in tennis. There's more to come."
She will take on 16-year-old Brenda Fruhvirtova next after the Czech became the youngest woman to win an Australian Open main-draw singles match since American Coco Gauff in 2020 with a 2-6 6-4 6-3 win over Romanian Ana Bogdan.
- This story was first published by [BBC https://www.bbc.com/sport/tennis/67973765]