Stefanos Tsitsipas beats champion Roger Federer to reach quarter-finals
20-year-old Greek fights back to win 6-7 (11-13) 7-6 (7-3) 7-5 7-6 (7-5)
Second seed Angelique Kerber stunned 6-0 6-2 by Danielle Collins
Fifth seed Sloane Stephens loses to Anastasia Pavlyuchenkova 7-6 (7-3) 3-6 3-6
World number two Rafael Nadal beats Tomas Berdych 6-0 6-1 7-6
*Federer 7-6 (13-11) 6-6 (1-3) Tsitsipas
Stefanos Tsitsipas looks annoyed as he overworks a cross-court forehand.
OH! Federer dobs a volley onto the baseline, it's called out, the umpire quickly overrules it - and we're going to have to replay the point!
Federer looks mutinous.
*Federer 7-6 (13-11) 6-6 (0-3) Tsitsipas
An ace from Stefanos Tsitsipas gets the crowd going and extends his lead.
Another big serve, called in. Federer challenges... and it is in by the tiniest of margins!
Two aces in a row for the Greek. He's 3-0 up.
Federer 7-6 (13-11) 6-6 (0-1) Tsitsipas*
Roger Federer will serve first - oh, and he sends a nasty forehand long first up!
Image source, EPA*Federer 7-6 (13-11) 6-6 Tsitsipas
This is the easiest service game Stefanos Tsitsipas has had for a while.
He holds to love, and we're going to a tie-break. Again.
Jonathan Jurejko
BBC Sport at Melbourne Park
Tsitsipas's serve has been creaking more than an old cottage door. He's staved off EIGHT break points in his past three service games - will he need a ninth life here?
Federer 7-6 (13-11) 6-5 Tsitsipas*
Stefanos Tsitsipas will serve to stay in the set once again.
Will it be easier than last time?
Federer 7-6 (13-11) 6-5 Tsitsipas*
Federer's run of points on serve comes to an end as he blazes a forehand into the foot of the net.
That's good from Tsitsipas, taking on a Federer second serve and smashing his way to 40-30, but the Greek misses a forehand to hand the Swiss a hold.
Jonathan Jurejko
BBC Sport at Melbourne Park
Federer has finally broken Tsitsipas. Sort of.
Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 live sports extra
The crowd are very pro Federer but should be loudly applauding Tsitsipas for surviving those set points.
Image source, EPA*Federer 7-6 (13-11) 5-5 Tsitsipas
Federer is nearly wrong-footed after serve-and-volleying, but he recovers in time to bob a winner over.
It's 15-0, and we're going to have to have a brief delay as Stefanos Tsitsipas has broken his shoelace.
Umpire James Keothavong announces this to the crowd, who all start laughing.
*Federer 7-6 (13-11) 5-5 Tsitsipas
For those keeping count, Federer is 0/10 on break points.
*Federer 7-6 (13-11) 5-5 Tsitsipas
Down the line aims Roger Federer - and misses!
Game, Stefanos Tsitsipas.
Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 live sports extra
Federer has faced some big shots from Tsitsipas on those break points.
What does Federer need to do to win one?
Image source, ReutersFederer 7-6 (13-11) 5-4 Tsitsipas*
That's a terrific serve from Tsitsipas, swinging down the T, and now it's game point to the Greek.
Federer 7-6 (13-11) 5-4 Tsitsipas*
And that's well-saved by Tsitsipas, charging forward from his serve and smashing a winner home.
40-40.
Federer 7-6 (13-11) 5-4 Tsitsipas*
That's an angry return of serve from Federer, letting rip with the forehand, and he's got his fourth set point.
Federer 7-6 (13-11) 5-4 Tsitsipas*
And again, Federer lets fly with an unforced error!
That's a forehand he should have made.
Hello, deuce. Again.
Federer 7-6 (13-11) 5-4 Tsitsipas*
Furious cross-court swipe from Federer, and Tsitsipas' reply misses the baseline.
Set point number three to Federer.
Federer 7-6 (13-11) 5-4 Tsitsipas*
Tsitsipas switches his serve up, going down the T, and Federer larrups his return long.
Deuce.
Federer 7-6 (13-11) 5-4 Tsitsipas*
Great return of serve from Federer, surprising Tsitsipas, and it's another set point for Federer.