Federer bunts volley after volley at Djokovic but he can't break through, and a Fed tweener finds the net for 0-15.

Ridonkulous defence from Djokovic, getting everything back, before Federer spears a forehand winner cross-court to end the rally.

Djokovic helps his opponent out with some wonky forehands but a couple of errors from the Swiss later and we're at deuce.

Federer ended a five-match losing streak against Djokovic at the ATP Finals last year, having previously not defeated him since the ATP Finals in 2015.

Federer is, however, bidding to end a five-match losing streak against Djokovic at the Grand Slams – he has not defeated Djokovic at a Grand Slam since his victory in the semi-finals at Wimbledon 2012.

Roger Federer gets a foothold on the Novak Djokovic serve first up, but it's quickly cancelled out as Djokovic's first serve comes to the party.

Djokovic loops a ball back at Federer and the overeager Swiss spears his passing shot way, way long.

40-15... and an ace wraps up a hold for Djoko.

Forward comes Roger Federer, volleying his way onto the board, and then the Swiss casually goes ace, ace, ace to hold in the blink of an eye.

Djokovic dominates the rallies and moves Federer around to take the first two points.

Federer gets on the board but he doesn't seem to hit the ball with any real anger and only a sloppy shot from Djokovic keeps the game going.

But an ace seals the game.

Djokovic plays quite a passive return game but he gets to 30-30 as Federer trips into a horrid double fault.

A bit of whip and curl and Federer wrongfoots Djokovic down the line with his forehand, and Djokovic nets out wide to hand Federer a hold.

Novak Djokovic blasts through his service game.

He dropped just four (!!) points on serve in that second set.

Honestly, that shot to win the second set was absolutely outrageous from Novak Djokovic.

He'll serve to get the third - and what feels like the final - set under way.

Jonathan Jurejko
BBC Sport at Melbourne Park

Gotta love a chant-off between two sets of passionate supporters.

Djokovic's lot start with a 'Nole! Nole! Nole!' before Team Federer quickly respond.

But it is Federer contingent who are quickly silenced. Djokovic, eyes popping and veins bulging, manically celebrating in their direction after clinching a two-sets-to-love lead.

Long way back for Federer...

Gigi Salmon
BBC 5 Live Sports Extra at Melbourne Park

Carrying a bit of a niggle, this has become an even bigger mountain for Federer to climb.

What a way to take the second set!

Novak Djokovic somehow scampers towards a drop shot, whips it back past Roger Federer and then roars at a... mostly silent crowd.

He's got one foot in the final.

Image source, AFP

OH, that's a brilliant return of serve from Djokovic from out wide!

A stretching Federer nets, and it's set point, Djokovic...

A big first serve sends Djokovic sprawling - and ranting at his box - but he's still in this as a backpedalling Federer floats his backhand into the net.

Roger Federer chips his way through a rally and then, with Djokovic back on the baseline, he shovels his volley into the top of the net.

30-30.

This has been an oddly... flat sort of set, but here we go.

Roger Federer rushes the net, and watches a backhand get walloped past him by Novak Djokovic.

After dropping the first point, Djokovic batters down big serve after big serve, and he holds to 15.

Roger Federer is trying to keep his points short but he moves well in this latest rally, feet sliding all over the show, and he outmuscles Novak Djokovic to go 30-0 up.

And, just like that, Federer notches up a love hold of his own.

That skyline, though...

Image source, Getty Images

Roger Federer gets the first point on the Novak Djokovic serve, which excites the crowd, and then Djokovic promptly rolls off three blistering points to rattle through a hold.

The crowd make some noise as Djokovic sends a return over the baseline, giving Federer game point.

And then a wide backhand hands Federer a hold!

Federer is clinging on by the skin of his teeth.

Image source, Getty Images