“I am not perfect, no?” said Jannik Sinner, the best tennis player in the world, during his post-match press conference late on Friday night. Sinner had just navigated his path back to the Australian Open final with another demonstration of his supreme mental toughness, recovering from a first-set deficit to ruthlessly defeat Ben Shelton, the 21st seed. Sinner maintains that there is more to come.

These are by far the best times of Sinner’s career so far, a period that has seen him finally break through at the biggest tournaments and firmly entrench himself at the top of his sport. Winning major titles is impressive enough, but the consistency he has established on a week to week basis has already separated him from many other champions.

These successes are all made even more interesting by the behind-the-scenes issues swirling in an unusually dramatic run to the final. Sinner played through health concerns in his fourth-round match against Holger Rune, then spent the final games of his win over Shelton cramping.

The most notable drama, however, is off the court. After Sinner was cleared of deliberate wrongdoing in his anti-doping case by an independent panel last August, the World Antidoping Agency (Wada) opted to appeal the verdict to the Court of Arbitration for Sport (CAS). Wada is not contesting Sinner’s argument that the banned substance clostebol entered his system through contamination. Under their rules of strict liability, which places the athlete at blame for everything that enters their body, they believe Sinner still carried some degree of fault due to the presence of the substance in his body. CAS will decide.

At the beginning of the tournament, Sinner was asked about the date of his upcoming trial. “I know exactly as much as you guys know. We are in a stage where we don’t know many, many things.” Hours later, CAS announced the hearing dates of 16-17 April.

“Nobody’s bulletproof,” said Darren Cahill, Sinner’s coach. “I think we all have moments when it gets to you a little bit, as well. To a large extent, he finds playing tennis matches to be his safe place. That’s where he can go and do his thing and feel like this is what he knows, this is what he understands, what is what he’s good at. It become a home for him to step on to the court and play tennis.”

On Sunday, he will attempt to defend his first grand slam title, which would be another rare achievement. Based on form and past performances in these occasions, Sinner begins the match as favourite against the world No 2 Alexander Zverev. While Sinner has played decisive, attacking tennis in the key moments of his most significant matches in the past year, Zverev’s career has so far been defined by his relative frailty when grand slam tournaments are on the line.

After leading Dominic Thiem by two sets in their 2020 US Open final, eventually standing two points away in a manic fifth set, he then established a two sets to one lead against Carlos Alcaraz in last year’s French Open final. Both times, Zverev froze in the tight moments and reverted back to his typical playing style, playing from many metres behind the baseline, simply putting the ball in play and praying that his opponents would miss. Zverev, an Olympic, ATP Finals and seven-times Masters 1000 champion, is by far the most successful player on either tour who has yet to win a major title. It is clear that Zverev must move past the scared, passive play that has defined his career in the decisive moments of finals.

In his third attempt at a grand slam title, Zverev will take solace from the fact that he has proven one of Sinner’s most difficult opponents. Between his defence, enormous serve and durability, he has successfully frustrated the Italian over the years. While Sinner won their first encounter at Roland Garros in 2020, Zverev won four matches in a row against the Italian until 2023, including inflicting Sinner his last grand slam hard court loss at the 2023 US Open.

Last year, however, Sinner pulled off a breakthrough win against Zverev in their first match since he became a grand slam champion, narrowly winning 7-6 (9), 5-7, 7-4 (4) in the semi-finals of the Cincinnati Open after three bruising sets. The stage on Sundayt will be several times greater than any other occasion in their previous match-ups and the pressure of battling for grand slam tournaments can do strange things to the mind, inspiring the best tennis from some and leaving others terrified. With a clean slate and a fresh opportunity for both, it remains to be seen which side they will fall on.