I think Nadal might have just called for the trainer? I'm not entirely sure, but the umpire is on the phone.

An unfazed Shapovalov rattles a sumptuous one-handed backhand winner down the line, before an excellently-timed ace wraps up a hold.

Shapovalov is racing away with this, and Nadal does not look happy.

WELL.

Nadal double faults!!

That felt like it was coming, Nadal taking an age to serve, and he pings his second serve well long to hand the break over to Shapovalov!

Nadal gets called for a time violation by the umpire as he waits to serve...

I'm not sure which way this one is going to go, you know.

Each player is creeping on the other one's serve, and it'll be Shapovalov who has first chance of an early break thanks to a wonky forehand from Nadal...

Nadal casts a filthy look at the net cord as his backhand rattles into the top of it and drops down to the floor.

Some good hustle from Shapovalov gets him out of any potential trouble, and he holds to 30 thanks to some big serves.

Oh!

Nadal is so far at the back of the court he's basically in the front row of seats but he reads Shapovalov's attempted smash, hammering it back to him, and Shapovalov makes a horrible mess of the volley and pushes it over the tramlines.

0-15.

That is excellent from Shapovalov, scrambling to meet a volley from Nadal and eventually popping away the winner.

Nadal responds with a gorgeous, fizzing forehand flick of his own that passes Shapovalov, and a missed backhand from the Canadian takes Nadal along to a hold.

Jonathan Jurejko
BBC Sport at Melbourne Park

You might recognise a familiar face in Denis Shapovalov's box.

Andy Murray's former coach Jamie Delgado is now coaching the Canadian after his partnership with the Scot came to an end of the last year.

Last weekend, Murray talked to BBC Sport about the decision to split: "He was not only my coach but he is a long-term friend.

"We had some great results and also been through some really tough years as well. To me it felt like that took its toll a little bit because we had been through so much together.

"When I started again I was not quite getting the results I wanted. Ideally we both wanted it to work out but it wasn't in the end and we had to move on, unfortunately.

"But he's got a great opportunity with Denis and I hope that goes well."

So far, it is going well.

Nadal wins an intense battle at the net first up, before a stretching Shapovalov puts his own volley down onto the ground.

Nadal is creeping into the Shapovalov serve but his returns aren't coming off quite as nicely as they were, and Shapovalov bats away successive forehand winners to hold.

That was... unexpected.

Nadal did drop the third set against Khachanov in the third round.

Shapovalov will serve to start this fourth set.

Well!

Denis Shapovalov lets fly with the backhand, and a winner gives him the third set!

What's Nadal got up his sleeve?

An ace, for starters. 15-40.

A twist!

Nadal shanks a forehand over the baseline and suddenly it's three set points to Shapovalov!

Well then...

Nadal coughs up a double fault of his own, and Shapovalov has a sniff at 0-30.

Shapovalov puts himself within one good serve of a love hold, before spearing down a double fault.

Not to matter, though, as the 14th seed watches Nadal flay a bouncy backhand one. That means Nadal will have to serve to stay in this set.

Blink and you'll miss it from Rafa Nadal.

He hurries through a love hold, wrapping up the game with a thunderous, unreturnable serve.

Great second serve again from Shapovalov, and Nadal can only fizzle a forehand long.

Shapovalov follows it up with an ace to get out of this game as quickly as he can.

Shapovalov produces a wicked second serve ace that just catches the line, and just as he gets himself within touching distance of the finishing line, he coughs up a double fault and we're at deuce.

Nadal picks an excellent time to find a huge serve.

Advantage, Nadal - and a backhand volley wraps it up! Clutch from the Spaniard.