Jannik Sinner came through the first true test of his comeback from a doping ban with Tuesday's straight-sets win over Francisco Cerundolo which took the world number one into the Italian Open quarter-finals.

Sinner accepted a three-month ban in February following an agreement with the World Anti-Doping Agency, which challenged an independent tribunal's decision to clear him of wrongdoing after two positive tests for the anabolic agent clostebol.

Carlos Alcaraz said Sunday that the pressure to reclaim the world number one ranking from the suspended Jannik Sinner has had a negative impact on his form this season.

Sinner received a three-month ban agreed with the World Anti-Doping Agency (WADA) in February after "admitting "partial responsibility" for team mistakes.

Jannik Sinner accepted on Saturday a three-month ban from tennis after the world number one admitted team mistakes led to him twice testing positive for traces of banned substance clostebol last year.

"He has lost only four or five matches in the past year, so it's crazy. I know people say who's better out of us. They say Jannik is better or some say me. It's all discussion."

Double Australian Open champion Jannik Sinner set his sights on mastering clay and grass courts to make himself a complete player after the Italian claimed his third hardcourt Grand Slam title on Sunday.

The 23-year-old came through a tense battle between the world's top two players 6-3, 7-6 (7/4), 6-3 on Rod Laver Arena, raising his arms in the air and looking to the sky in celebration.

The victory earned the Italian world number one his third Grand Slam crown.

Sinner's coach Darren Cahill said it was no surprise for him to see his young charge back in the final, but they were wary of the threat posed by Zverev's overarching desire to finally win a Slam.

The Italian top seed faces Ben Shelton on Friday, just two matches away from a first successful Grand Slam title defence after winning his maiden major crown in Melbourne last year.

The Italian world number one showed no signs of the illness that hampered him in his last match to emphatically fly past the eighth seed 6-3, 6-2, 6-1 on Rod Laver Arena.

Defending champion and top seed Jannik Sinner overcame a debilitating medical episode as well as Dane Holger Rune to reach the quarter-finals of the Australian Open for the third time with a 6-3 3-6 6-3 6-2 victory on Monday.

The first Grand Slam of the year gets under way at Melbourne Park as a 15-day event for the second year running, aimed at cutting down on late-night finishes.

Alcaraz won the French Open and Wimbledon titles last year while Sinner claimed the Australian Open and U.S. Open trophies as the pair heralded a new era for the men's game by shutting out 24-times Grand Slam champion Novak Djokovic.

For over two decades, the "Big Three" of Roger Federer, Rafael Nadal, and Novak Djokovic dominated the sport, pushing each other to unimaginable heights. Now, a new story begins.

Zverev trails world number one Italian Jannik Sinner by more than 3,000 ranking points, but his confidence is high after winning the Rome and Paris Masters 1000 titles in recent months.

Novak Djokovic is ready to challenge Jannik Sinner and Carlos Alcaraz at the Grand Slam stage when he returns to action at the Australian Open after an underwhelming campaign this year, the 24-times champion said.

The world number one eased to a 7-6 (7/2), 6-2 triumph against Tallon Griekspoor for the winning point after Matteo Berrettini had put the defending champions ahead with a convincing 6-4, 6-2 win against Botic van de Zandschulp.

World number one Jannik Sinner was described as a "puzzle that not many have solved" after defeating Alex de Minaur to power holders Italy into the Davis Cup final with a 2-0 victory over Australia on Saturday.