Top seed Rafael Nadal showed his fighting qualities as he battled through his Australian Open first-round match against Jack Draper.
World No.1 Iga Swiatek also had her struggles in the women's draw, but she too got the job done versus Wimbledon quarter-finalist Jule Niemeier to take her place in the second round.
There were emphatic wins on day one for Daniil Medvedev, Jannik Sinner, Stefanos Tsitsipas and Maria Sakkari as the tournament got under way at Melbourne Park.
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Nadal wins but is he playing well enough to win slam 23?
Nadal progressed in four sets against Britain's Draper, 7-5 2-6 6-4 6-1, but it was far from an easy match for the defending champion.
After edging Draper in the first set, Nadal found himself dropping the second and a break down in the third before fighting back to claim what looked like a deceptively comfortable win on paper.
The Spaniard had lost six of his last seven matches heading into the first slam of the year and will just be pleased to get his title bid off to a winning start.
"I needed a victory, so that's the main thing," Nadal said post match. "It doesn't matter the way.
"The most important thing today is a victory against a tough opponent. To win against Jack, as I said before the tournament start, has been one of the toughest first rounds possible, being seeded.
"We know [it was] not going to be perfect, as I said the other day.
"But to win against Jack, I need to do things well, no? I think I did things well. So [I'm] satisfied with the victory, because that gives me the chance to play after tomorrow again."
Nadal will face USA's Mackenzie McDonald in the second round, who defeated countryman Brandon Nakishima in five sets.
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Swiatek battles through against Wimbledon quarter-finalist
Despite winning in straight sets against Niemeier 6-4 7-5, Swiatek struggled throughout her opening match, with the German taking advantage of her second serves. Swiatek could only get 49 per cent of her first serves in play.
The Polish top seed just shaded the Wimbledon quarter-finalist in the first set before finding herself 5-3 down in the second.
However, Swiatek reeled off four consecutive games to get the job done and set up a contest with Colombian Camila Osorio in the next round.
🇵🇱 1GA ☝️ pic.twitter.com/XImiczOTMD
— #AusOpen (@AustralianOpen) January 16, 2023
Medvedev, Sinner secure brutal wins
Australian Open 2022 finalist Medvedev showed no mercy as he clinically destroyed USA's Marcus Giron 6-0 6-1 6-2.
The Russian seventh seed's form hasn't been brilliant since he lost the decider to Nadal at Melbourne Park last year, failing to get past the fourth round in the French Open and US Open while being banned from Wimbledon due to his country's invasion of Ukraine.
But he looks to be in great shape to challenge Down Under, with the best performance of any men's player on day one.
A great start for @DaniilMedwed!
— #AusOpen (@AustralianOpen) January 16, 2023
The No.7 seed was very, very, very good tonight, beating Marcos Giron 6-0 6-1 6-2 in a tick over 90 minutes.
He'll face John Millman on Wednesday! 👀#AusOpen • #AO2023 pic.twitter.com/Rn8YF8G0RV
Young gun Sinner enjoyed a similarly spectacular win as he thrashed Brit Kyle Edmund 6-4 6-0 6-2 in a warning sign for other Australian Open contenders.
The Italian 15th seed, aged 21, has been threatening to emerge in the same vein as world No.1 Carlos Alcaraz has, and it could be his turn at Melbourne Park in 2023.
Greece lightning victories for Tsitsipas and Sakkari
It was a great day for Greece, with both Tsitsipas and Sakkari showing they are in excellent form during easy wins.
Third seed Tsitsipas swept past Frenchman Quentin Halys in straight sets 6-3 6-4 7-6 (8-6) and will next meet Australian wildcard Rinky Hijikata in the second round.
Meanwhile, Sakkari showed her superiority against China's Yue Yuan in a 6-1 6-4 victory to set up a meeting with teenage Russian qualifier Diana Shnaider.
