This is so unlike the Novak Djokovic we're used to seeing on the sport's major stages.

The Serb's unforced error count has risen to 23, while hitting just 11 winners. He just cannot get going here.

Lorenzo Musetti is capitalising with some stunning shots and holds serve to 15 with an ace.

The Italian is in a dream position here at a set and a break up against the 10-time champion.

Long from Novak Djokovic!

That is a remarkable five unforced errors in the space of six points as Djokovic chucks away a 30-0 lead in suffering his latest setback.

Image source, Reuters

The body language still isn't great from Novak Djokovic despite finding an immediate response, and he shakes his head after missing a backhand to bring Lorenzo Musetti into the game.

Another poor miss allows Musetti to 30-30, but Djokovic takes an important fifth point by following solid defence with a winner.

There's more head-shaking to come, however. Deuce.

It's certainly not been going Novak Djokovic's way of late, but the fourth seed will have a look at three break points here following a string of unforced errors by Lorenzo Musetti.

It's quite the gift for Djokovic, who breaks back to love as we tick over into a second hour.

Too good!

Lorenzo Musetti is putting on a real show on Rod Laver Arena. Novak Djokovic is brought to the net before being lobbed by an exquisite forehand.

The Italian has an immediate breakthrough in the second set, and he's now won seven of the past nine games in this match.

Can Novak Djokovic reset? Can Lorenzo Musetti maintain his high level?

The first couple of points of set two suggest nothing has changed just yet as Musetti lands back-to-back winners - the second a superb angled backhand.

And another! Three break points.

Lorenzo Musetti halts Novak Djokovic's progress with an ace for 15-15, and another powerful first serve helps him edge ahead.

And the Italian won't be denied here! An excellent forehand seals the first set point.

Lots for Djokovic to think about before beginning set two.

Only a hold of serve will do for Novak Djokovic here as he attempts to salvage this first set.

He manages to achieve exactly that, sealed with an ace at 40-15, to force Lorenzo Musetti to try and see out the opener.

Novak Djokovic raises his arms and looks to the sky after missing the most routine of volleys at the net with the court at his mercy. That is so not like him.

It likely wouldn't have changed the outcome, as Musetti continues uninterrupted to a hold to love, but it's the latest sign that all is not well for the 10-time champion.

If any picture could sum up how this has gone so far for Novak Djokovic, it's this one.

A quite puzzling start to this match by the 24-time major winner.

Image source, Reuters

The frustration builds for Novak Djokovic as a second game point passes him by, but he escapes at the third opportunity as Lorenzo Musetti nets a return.

That's a four-game run against him ended - but it's still Musetti in charge.

Novak Djokovic manages to put together a series of decent points to recover the situation - for now.

He gets Lorenzo Musetti on the run and eventually draws the error from his energetic opponent for deuce.

From 0-40 to game point, but Djokovic misses the line and the danger isn't over yet...

Lorenzo Musetti just can't miss at the moment!

The Italian strokes a wonderful one-handed backhand cross-court and beyond the reach of his opponent, who is muttering to himself as he prepares to serve at 0-30 down.

And now he must face three more break points.

Wow, what is going on with Djokovic here?!

It's been a strange start by Novak Djokovic. His unforced errors count is now up to 13 after five games - to just five winners.

Lorenzo Musetti, by comparison, has six winners to five unforced errors.

Musetti races to a love hold to take charge of the first set from 2-0 down. Very interesting...

Image source, Getty Images

Novak Djokovic, after a positive start, is faltering. The unforced errors are really beginning to stack up for the 10-time winner.

Lorenzo Musetti adds a touch of class with a winner down the line for break points - and it's the Italian, in the ascendancy now, who is the next to strike to claim a third consecutive game.

After a less than ideal start against a serial winner whom he has managed to get the better of just once in 10 attempts, Lorenzo Musetti looks to be gaining momentum as he moves to 40-15 on serve.

He fails to finish off a point when well-positioned at 40-30, allowing Djokovic to battle back to deuce, but the Serb pulls a backhand wide and we're all level in the first set.

Image source, Getty Images

Lorenzo Musetti's career has been on an upward trajectory for a decent while and today he has the chance to reach a third Grand Slam semi-final.

The Italian fifth seed, 23, has already been to the last four at the French Open and Wimbledon, and this is his best ever run in Melbourne.

His head-to-head record with Novak Djokovic doesn't make for the best reading, though: played 10, won one. That victory came at the Masters event on the Monte Carlo clay in 2023.

All three Grand Slam meetings have gone the way of the Serb, who also beat Musetti on his way to winning Olympic gold at Paris 2024.

Novak Djokovic can only laugh to himself after missing an overhead and handing over a break back point to Lorenzo Musetti.

The Italian can't take his first opportunity, but he'll get a second look as he skips up into a forehand at the net and wrongfoots Djokovic.

Another miss from Djokovic! His seventh unforced error in three games brings Musetti back on serve. The former world number one is not entirely happy so far.

He may already be a couple of games to the good, but Novak Djokovic is visibly frustrated with himself after he misses at the net as he seeks to take charge on serve.

A delightful drop shot is weighted so perfectly that even the fleet-footed Lorenzo Musetti can't recover it - but Djokovic lets out an audible groan after knocking a backhand into the net for deuce.

Image source, Getty Images

As Novak Djokovic continues his bid for a 25th Grand Slam singles title, are the stars aligning for the 38-year-old Serb to finally break the record?

Djokovic was scheduled to play Jakub Mensik in the fourth round on Monday but the Czech player pulled out injured, meaning Djokovic has had three full days of rest before today's quarter-final against Lorenzo Musetti.

Conserving energy will be a key factor in his chances of lifting the trophy on Sunday, so winning his first three matches in straight sets has also helped his cause.