Novak Djokovic raged about a "drunk" fan and struggled with his injured hamstring but on a day where big names tumbled, the nine-times champion stood tall.
Earlier, Australia's Alexei Popyrin put on a serving display to produce one of the biggest upsets of the tournament as the world number 113 defeated world number nine Taylor Fritz.
The draw was earlier blown wide open by second seed Casper Ruud's upset loss to Jenson Brooksby.
Check back on all the action from day four below.
Key events
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That's a wrap
By Paul Johnson
Thanks for joining us again today tennis fans.
Have no fear we've got Thanasi Kokkinakis and Andy Murray covered.
The talented Luke Pentony will be wrapping that one up as it goes past my bedtime.
But go Thanasi!
De Minaur advances
By Paul Johnson
Alex De Minaur is also through to the third round.
The Australian was made to work for it by Frenchman Adrian Mannarino but eventually his class shone through as he recorded a 7-6 (7/3) 4-6, 6-4, 6-1 victory.
The match proved to be a war of attrition and went over three-and-a-half hours before De Minaur prevailed to become the second Australian into the 3rd round this year.
There he will face another Frenchman, Benjamin Bonzi, after he upset Spanish 14th seed Pablo Carreno Busta in 5 sets.
Djokovic advances despite drama
By Paul Johnson
Novak Djokovic has overcome his troublesome hamstring, plucky French qualifier Enzo Couacaud and an unruly crowd to keep his bid for a 10th Australian Open title on track.
On a day where men's seeds tumbled it was a night of high drama on Rod Laver Arena.
Djokovic eventually won the match 6-1, 6-7 (7/5), 6-2, 6-0 before a frenzied crowd.
Some members of that crowd were ejected late on after Djokovic complained to chair umpire Fergus Murphy that one of a group had been heckling him since the first point of the match.
"The guy is drunk out of his mind," Djokovic said.
"From the first point he's been provoking me.
"He is not here to watch tennis, he just wants to get in my head."
The group were banished in a bizarre fourth set where Djokovic had been cruising before he turned to the chair to complain about the crowd.
It wasn't the only drama to take place though.
Both players received medical treatment, Couacaud in the opening set and then in the second Djokovic.
The Serb left the court for treatment on his hamstring, which he pulled up short on a couple of times in the match before he went for treatment.
It was the opening Couacaud needed as he fought hard in the second set to take it from Djokovic.
The crowd played a part there too, distracting Djokovic between serves on a crucial point, he double-faulted and then Couacaud took the set.
But his comeback would be short lived as Djokovic blew him off the court in the end.
Djokovic didn't say a lot post match put paid credit to his 190th-ranked opponent.
"There was a lot happening in tonight's match," Djokovic said.
"Enzo deserves credit for the fight, and especially pushing the match to a fourth set.
" We both had some medical timeouts and struggled a little bit."
'Drunk out of his mind': Djokovic erupts over crowd
By Paul Johnson
Up a set and a break Novak Djokovic has just erupted at chair umpire Fergus Murphy over a member of the crowd he says has been heckling him since the beginning of the match.
Djokovic even pointed the fan in question out as someone dressed as 'Where's Wally'.
He was 2-0, 40-30 up when he enacted Nick Kyrgios at Wimbledon, who infamously said a fan during their final "had 700 drinks bro" to the chair umpire.
On this occasion Djokovic demanded the fan in question be kicked out.
"The guy is drunk out of his mind," Djokovic said.
"From the first point he's been provoking me.
"He is not here to watch tennis, he just wants to get in my head.
"What are you going to do about it?
"Why don't you get security? Get him out of the stadium."
Djokovic then eventually held serve to lead 3-0 in the fourth set.
Security then ejected the fans at the change of ends.
De Minaur takes the third
By Paul Johnson
Over on John Cain Arena Alex De Minaur is whipping the crowd into a frenzy after taking the third set from Adrian Mannarino.
De Minaur broke the Frenchman at 4-all in the third set and then the crowd erupted as he served it out.
Djokovic takes the 3rd
By Paul Johnson
That changed quickly.
Djokovic really doesn't look like he wants to run too much but when you strike the ball as well as him you don't have to.
The Serb unleashed on some massive forehands throughout the set but an early break really set him up to take it 6-2 and give himself a two sets to one lead.
What's interesting is the shot that he seems to be missing most is the backhand.
Some seeds finally winning
By Paul Johnson
Swiss star Belinda Bencic, who was dominant on her way to the Adelaide 2 title is through to the third round.
She defeated American Claire Liu 7-6 (7/3), 6-3.
Bencic will play Italy's Camila Giorgi in the third round.
While out on Court 7 Spain's Roberto Bautista-Agut rallied back from 2 sets down to defeat American qualifier Brandon Holt 4-6, 2-6, 6-3, 6-2, 6-2.
Mannarino levels up with the Demon
By Paul Johnson
This one was never going to be easy for De Minaur and after getting the break in the opening game of the second set, Mannarino takes it 6-4.
Couacaud takes the 2nd set
By Paul Johnson
Well.
That was something.
The crowd got right at Djokovic there and made a heap of noise between first and second serves at 5-all.
Totally not on.
But Djokovic chucked in a double fault and then sent an easy backhand long to give Couacaud the second set.
That was all after Djokovic led the tiebreak 3-0.
This one is now even more interesting.
Can the Djokovic hamstring hold on? Can Couacaud keep up his level?
Stay with us to find out.
We're now off to a 2nd set tiebreak
By Paul Johnson
And this one feels more pivotal than usual.
Djokovic calls for the trainer
By Paul Johnson
Feels a bit like deja vu.
Yesterday it was Nadal calling for the trainer and now it's Djokovic.
Of course Djokovic has been struggling with his hamstring since Adelaide but at the end of that last Couacaud service game the Serbian pulled up proppy.
He's since called for the trainer and is currently receiving treatment off the court.
Djokovic has returned since and is now pushing really hard.
One gets the sense he wants to get this one over with sooner than later.
De Minaur goes up a set
By Paul Johnson
But this has been far from easy.
Adrian Mannarino, who has just about the loosest strings on tour, is giving De Minaur all he can handle, especially with the wide slider to the second court.
De Minaur though has persevered and taken the opening set in a breaker.
Djoker is cruising
By Paul Johnson
As everyone else seems to be tumbling around him, guess who is dominant?
That's right, the guy chasing his 10 Australian Open crown.
Novak Djokovic could not look more comfortable if he tried and his opponent, Enzo Couacaud, who was already out of his depth has had to have his knee taped.
This one could be quicker than a hiccup.
Djokovic has taken the opening set 6-1.
Few of you loving 'Poppy'
By Paul Johnson
Dulcie
Just so proud of our young players
Herbie Psaila
Another young gun doing Australia proud. We don’t need self obsessed big heads like Kyrgios to make these games a success. I’m not hearing the critic’s bellowing about drawcard names not competing anymore!
Alison
Wonderful match Alexei
Zverev gone too as upsets continue
By Paul Johnson
Will the men's seeds keep tumbling? It seems that way.
Though to be fair after a severe ankle injury sustained last year Alexander Zverev was not expected to go far this Australian Open.
But getting rolled by a lucky loser, that's something else.
Still full credit to America's Michael Mmoh who rolled Zverev in four sets 6-7, 6-4,6-3, 6-2.
The German again struggled with his sketchy second serve and gave up 12 double faults for the match in a performance well below his lofty best.
Mmoh, who had only ever made the second round of a slam will next face fellow American JJ Wolf.
Popyrin stuns Fritz
By Paul Johnson
Australian wildcard Alexei Popyrin has claimed the biggest win of his career, sending world number 9 Taylor Fritz packing at the Australian Open.
The Australian, ranked 113 in the world, played to his potential and not his ranking as he put on a serving clinic to dismiss Fritz 6-7, 7-6, 6-4, 6-7, 6-2 in front of a raucous crowd on John Cain Arena.
As the crowd serenaded him with chants of "Poppy", an emotional Popyrin, who won just five matches on the main tour in an awful 2022, said this win meant the world to him.
"You guys were just incredible. Oh my God, this is crazy," Popyrin said.
"This win means so much to me.
"I won as many matches this year as I did the whole of last year and it's only January.
"This is a dream for me and I don't want to wake up at all."
The win marks the latest upset for Popyrin, who holds victories over some of the sport's biggest stars including Dominic Thiem and Grigor Dimitrov.
The victory over Fritz, who is one of tennis' fastest-rising stars, is among the best of them.
Fritz at times complained about the more vocal elements of the crowd and also received an injury timeout for treatment to his right leg after pulling up short while moving to a backhand.
But while the American's leg seemed to recover, his game did not.
Fritz took more than three hours to get a break point on the Popyrin serve, but when he did the American took his chance and took a 5-4 lead in the fourth set.
He could not finish though. A loose game and some brilliant returning from Popyrin saw the Australian break straight back.
It was not long before the pair were off to another tiebreak and, though Fritz got the early mini-break, Popyrin fought back and had match point at 6-5.
A big Fritz serve/forehand combo put an end to that before he almost bored Popyrin into a backhand error when he had set point at 7-6.
Fritz was buoyed by that and came out swinging in the final set, forcing Popyrin to save a break point in the opening game with an ace, but from there it was all Popyrin.
The Australian broke Fritz with ease for a 3-1 lead and remained untroubled on his own serve.
But he didn't need it, breaking Fritz for a five-set victory with a massive forehand.
Popyrin breaks!
By Paul Johnson
It's now 3-1 to the Aussie in the 5th set.
The way he has been serving this could now be academic.
Bird dumps on struggling Zverev
By Paul Johnson
The Alexander Zverev comeback continues to hit speedhumps.
The German is now down 2 sets to 1 against American qualifier Michael Mmoh.
But he has also had to suffer the indignity of being dumped on by a bird... literally.
The local wildlife clearly not amused by his service struggles and showed the German what they thought, forcing him to get that tangle out of his blond mane.
In case anyone is keeping count of how many doubles the German has now hit, it's 8 and rising.
Popyrin, Fritz off to a 5th
By Paul Johnson
That tiebreak was tense.
Fritz set the tone early and had the mini-break but Popyrin fought his way back to level pegging and even had a match point at 6-5.
But Fritz, ever calm managed to stave it off with a big serve and big forehand to force the error.
The American eight seed then needed just one set point to take the breaker as he rallied Popyrin into an error on what was a passive point from both players.
Big set coming up here and the hometown support for Popyrin is massive.
