Tsitsipas, speaking on court: "I had an aggressive mindset from the start, stayed in the moment, got first serves in and tried to press. I didn't lose my patience and that was the key.
"I showed fighting spirit and had most of the crowd supporting me. I haven't seen such a large crowd all my life. The atmosphere, the vibes and the energy shown to Roger and me today was indescribable."
Post update
"Welcome to the future of tennis...."
Video content
Video caption: 'Welcome to the future of tennis!' - Tsitsipas wins point with spectacular diving volley'Welcome to the future of tennis!' - Tsitsipas wins point with spectacular diving volley
...I feel like everyone needs a lie down after that.
'Happiest man on earth'
Tsitsipas tells John McEnroe: "There's nothing I can describe it to. I am the happiest man on earth.
"From the beginning I went in believing in myself and my abilities. Roger is a legend, he showed such a good tennis over the years, I've been analysing him since the age of six, and this is a dream to face him.
He has beaten Roger Federer, the defending champion, the six-time winner in Melbourne, the 20-time Grand Slam winner, to reach the Australian Open quarter-finals.
Live Reporting
Amy Lofthouse
All times stated are UK
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Latest PostGoodbye!
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
And breathe...
Right, we're going to leave this live text here, but stick with 5 live sports extra for commentary of Sloane Stephens v Anastasia Pavlyuchenkova.
There's also highlights tonight on BBC Two at 17:15 of the day's play in Melbourne.
I'm going to leave you all with this superb Tweet from the man who has just played out of his skin to beat Roger Federer.
'Atmosphere and vibes indescribable'
Tsitsipas, speaking on court: "I had an aggressive mindset from the start, stayed in the moment, got first serves in and tried to press. I didn't lose my patience and that was the key.
"I showed fighting spirit and had most of the crowd supporting me. I haven't seen such a large crowd all my life. The atmosphere, the vibes and the energy shown to Roger and me today was indescribable."
Post update
"Welcome to the future of tennis...."
Video content
Post update
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
We're just seeing footage of the Greek fans who were watching the match outside the Rod Laver Arena on one of the big screens.
Jubilant doesn't even begin to cover it.
Post update
And if you'd like to learn more about history-maker Stefanos Tsitsipas, then just read on...
Post update
Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 live sports extra
Federer didn't play a bad match. It was the inspired play of Tsitsipas who from the start played to a great level.
He gave his all and it's a thoroughly deserving victory.
We've seen the changing of the guard.
Post update
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
...I feel like everyone needs a lie down after that.
'Happiest man on earth'
Tsitsipas tells John McEnroe: "There's nothing I can describe it to. I am the happiest man on earth.
"From the beginning I went in believing in myself and my abilities. Roger is a legend, he showed such a good tennis over the years, I've been analysing him since the age of six, and this is a dream to face him.
"Winning this - I cannot describe it."
Post update
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
Stefanos Tsitsipas finishes with 20 aces, 62 winners and 36 unforced errors.
He saved all 12 break points he faced and won 78% of points on first serve.
I just... what a performance.
Post update
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
Changing of the guard, anyone...?
Post update
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
Tsitsipas is near tears. Half his support box are crying. He's getting a continued standing ovation from the crowd.
"The happiest man on earth," he says.
Post update
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
As a kid, Stefanos Tsitsipas was watching videos of Roger Federer on Youtube and mimicking his backhand.
Now, as 20-year-old, he's beaten him in a Grand Slam.
Just astonishing.
Game, set and match - Tsitsipas
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-7 (5-7) Tsitsipas
STEFANOS TSITSIPAS HAS DONE IT!
He has beaten Roger Federer, the defending champion, the six-time winner in Melbourne, the 20-time Grand Slam winner, to reach the Australian Open quarter-finals.
WHAT a story.
Tie-break
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-6 (5-6) Tsitsipas*
A late call of "out!" from the line judge on a Federer forehand.
Everyone thought it was from the crowd but it wasn't.
Federer challenges... it's out!
MATCH POINT, TSITSIPAS.
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Gigi Salmon
Radio 5 live sports extra tennis commentator at Melbourne Park
Tsitsipas is frighteningly close to the finish line.
He says he wants to raise the profile of tennis in Greece - well he's done that!
Tie-break
*Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-6 (5-5) Tsitsipas
Ace from Federer!
Tsitsipas challenges... but it's in.
5-5.
Tie-break
*Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-6 (4-5) Tsitsipas
Ridiculous return of serve from Roger Federer, but he can't capitalise and his backhand finds the foot of the net!
Tie-break
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-6 (4-4) Tsitsipas*
Federer tries to pass Tsitsipas at the net, and misses.
Tie-break
Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-6 (4-3) Tsitsipas*
Stefanos Tsitsipas rushes to a drop shot, reading Federer's mind... and misses!
Tie-break
*Federer 7-6 (13-11) 6-7 (3-7) 5-7 6-6 (3-3) Tsitsipas
Stefanos Tsitsipas gets moved around behind the baseline, and he nets!
Change of ends. How's the nerves?