It only took Novak Djokovic two games into his Australian Open semifinal against Jannik Sinner to realise that he wasn't going to have it all his own way on Rod Laver Arena.

In his opening service game, the 10-time Melbourne Park winner was broken, leaving him with his back up against the wall.

It was a position from which the world number one struggled to recover, with Sinner securing a second break during the first set, which he won 6-1 in a brisk 35 minutes.

Another double break and Djokovic's growing number of unforced errors helped Sinner wrap up the second set and establish a commanding lead.

Djokovic knows what it takes to fight back from two sets to love down and win a best-of-five match.

He has pulled off the feat eight times during his career and as recently as last year's US Open.

Djokovic began to climb off the canvas by claiming the third set against Sinner, despite facing a match point in the tiebreak, but it was a brief reprieve.

Sinner took a 3-1 lead in the fourth set when he broke Djokovic for the fifth time and with the finish line in sight, proceeded to ice a 6-1, 6-2, 6-7 (6/8), 6-3 win and reach his first final of a major.

The result will provide shock value to some, considering Djokovic's outstanding record at the Australian Open.

He has the most championship wins in the Open era and was on a 33-match winning streak in Melbourne — stretching back to 2018 — before facing Sinner.

But his defeat to the Italian world number four shouldn't come as a surprise.

Sinner is moving into his prime as a player and he's learned not to be intimidated by the Serb.

He was 0-3 against Djokovic in their career head-to-head meetings but won two of the past three matches, including their most recent clash in last year's Davis Cup semifinals.

Sinner had not dropped a set in Melbourne before playing Djokovic, having impressively seen off the challenges of highly credentialed rivals such as Andrey Rublev and Karen Khachanov.

The 22-year-old was virtually untroubled on his serve in Friday's semifinal, illustrated by the fact he didn't give up a single break point.

He kept his unforced error tally to 28, a stark contrast to the 54 posted by Djokovic.

Djokovic's cause was not helped by a below-par serving performance, highlighted by the four breaks he conceded across the opening two sets.

He was particularly poor in the opening set when he could only nail 43 per cent of his first serves.

Djokovic turns 37 in May, but it would be foolish to write off the 24-time major winner or suggest his best days are gone.

Only last year, he won three slams at the Australian, French and US Opens, and lost in a five-setter to Carlos Alcaraz in the Wimbledon final.

While his form in Melbourne never looked convincing, the impact of a pre-tournament wrist injury and an illness he battled in Melbourne may come to light now his tournament is over.

His reign at the top isn't at an end but among his challengers, he knows Sinner is closer than ever before.