Tsitsipas saves set pointpublished at 10:01 Greenwich Mean Time 20 January 2019
Federer 7-6 (13-11) 5-4 Tsitsipas*
HELLO!
Big, quick first serve out wide from Tsitsipas to save set point!
Deuce.
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
Amy Lofthouse
Federer 7-6 (13-11) 5-4 Tsitsipas*
HELLO!
Big, quick first serve out wide from Tsitsipas to save set point!
Deuce.
Federer 7-6 (13-11) 5-4 Tsitsipas*
A cracking rally, backhands and forehands flying, and eventually it's Tsitsipas, jogging forward to a Federer slice, who drifts his shot long.
Set point, Federer...
Jonathan Jurejko
BBC Sport at Melbourne Park
The tension is lifted by one Fed Head, or an attention-seeking drunk at the very least, screaming how much he loves the Swiss great.
That brings a few laughs from the engrossed largely pro-Federer crowd, who are being put through the wringer as much as their man.
Federer doesn't flinch and cracks down a first serve on his way to a hold-to-love.
Federer 7-6 (13-11) 5-4 Tsitsipas*
Tsitipas' last service game? 13 minutes long.
Federer's? It's lasted two minutes.
He holds to love.
*Federer 7-6 (13-11) 4-4 Tsitsipas
A return of serve drifts long from Federer.
Game point, Tsitsipas - and he holds as Federer sends his backhand into the net!
It's not been easy, but Tsitsipas is hanging in there. We're still on serve.
Federer 7-6 (13-11) 4-3 Tsitsipas*
He's none from six now!
Federer has an opportunity to pass Tsitsipas with the backhand, and instead he thuds his shot over the baseline.
Federer 7-6 (13-11) 4-3 Tsitsipas*
Break point, Federer, as a Tsitsipas backhand goes long.
Federer is none from five on break points.
Federer 7-6 (13-11) 4-3 Tsitsipas*
A slam from Tsitsipas leaves Federer leaping through the air like a show pony, trying to get the ball and ending up thwacking at fresh air.
That's a difficult volley to make, though, and Tsitsipas mistimes his shot. Deuce.
Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 live sports extra
There's been tension in a number of Tsitsipas' service games but he has survived them all so far.
Federer 7-6 (13-11) 4-3 Tsitsipas*
Lovely, lovely stuff from Tsitsipas, following up an elegant backhand with a dinky volley, and he's got the advantage.
A nibble off the net falls against the Greek, though, and Federer smashes game point into the corner of the court.
Federer 7-6 (13-11) 4-3 Tsitsipas*
A chance for Federer as Tsitsipas comes forward, but he nets his backhand.
Oh, and then a great swipe down the line, followed by an error from Tsitsipas, takes us back to deuce.
Jonathan Jurejko
BBC Sport at Melbourne Park
The breeze is picking up inside Laver as the night gets a little chillier.
That's contributing to Tsitsipas struggling to get his ball toss right, three times in this game alone he has hit the reset button after throwing it up.
Federer 7-6 (13-11) 4-3 Tsitsipas*
Tsitsipas hangs his head in annoyance as his ball toss goes wrong, but he's on top as a stretched Federer spears a return of serve long.
We're going back to deuce, though, as Tsitsipas errs down the line.
Federer 7-6 (13-11) 4-3 Tsitsipas*
A cross-court winner from Federer gets him his first point on the Tsitsipas serve, before he comes forward and pops a gorgeous backhand down the line.
Tsitsipas closes that down with some big, swinging serves, getting to 40-30, but Federer somehow angles a backhand winner down the line to bring up deuce.
Jonathan Jurejko
BBC Sport at Melbourne Park
Thinking this could be a procession now? Think again.
We know Stefanos Tsitsipas used to watch YouTube videos of Federer - wonder if he has watched his matches against Kevin Anderson at Wimbledon and John Millman at the US Open last year?
Federer led both those matches - a two-set advantage against Anderson - and then.... lost.
I'm not convinced the ageing Federer is as sure of himself as he was...
Federer 7-6 (13-11) 4-3 Tsitsipas*
Federer comes into the net to take control of this game - that's the maestro at his best -and then bashes down two aces out wide to hold serve with ease.
*Federer 7-6 (13-11) 3-3 Tsitsipas
Huge first serve from Tsitsipas, and that's not coming back.
Backhand meets backhand - and then Tsitsipas changes direction to go down the line with a winner!
Three break points staved off by the Greek.
Federer 7-6 (13-11) 3-2 Tsitsipas*
WHAT a volley from Stefanos Tsitsipas!
Federer could have got to it but for some reason, he stops, and then gives himself a stern talking-to.
Federer 7-6 (13-11) 3-2 Tsitsipas*
Tsitsipas runs round to set himself up for another cross-court winner - and instead the ball hits the middle of the net.
Another door opens for Federer...
Federer 7-6 (13-11) 3-2 Tsitsipas*
Stefanos Tsitsipas gets his nose in front with a cross-court forehand that Federer can only spoon invitingly into the air.
Whoops. That forehand has gone a little wonky though, Tsitsipas hitting the ball long, and we're going back to deuce.