Russell Fuller
BBC tennis correspondent at Melbourne Park

Berdych handled the heat in that last rally so well, but Federer did not miss a beat.

Federer brings up another break point but that also goes amiss.

Then the defending champion stifles a set point for Berdych.

Another trip to deuce follows before a fourth break point for Federer.

He steals it with a brilliant backhand winner.

That game was madddddddd.

Image source, Getty Images

Image source, Getty Images

Houston, we have a problem.

Federer has challenged a call on Berdych's serve. The ball was called in, Fed thinks it's out.

Hawk-Eye says it is in, but unfortunately it doesn't want to display the graphic to prove it to everyone. The chair umpire moves uncomfortably in his high position, comes to the mic and explains that the decision of 'in' stands.

Federer goes and has a word but it won't make a difference. He's also lost his challenge.

We go on...and Federer misses out on the break opportunity.

Mark Woodforde
Australian 12-time Grand Slam doubles champion on BBC Radio 5 live sports extra

That was not the time to attempt a shot like that.

It looks like Berdych has double-faulted...until Hawk-Eye reveals his second serve was in by the skin of its teeth.

A forehand error from the world number 20 makes it 15-30.

A fired-up rally ensues, and Berdych crucifies a backhand down the line which goes way out.

It's time for Federer to try and fight back with two break points.

Mark Woodforde
Australian 12-time Grand Slam doubles champion on BBC Radio 5 live sports extra

When Federer lands that first serve, his win rate is extremely high. It's almost at 90%. This is the moment of truth for Berdych, to see if he can remain strong behind his serve.

Image source, AFP

Federer is serving to stay in the set.

He plonks a forehand wide after a deep return from Berdych, before pinging a crowd-pleasing backhand cross-court for 15-15.

Then an ace for 30-15.

Another big serve nullifies Berdych's response and then the Czech lifts the ball over the line.

A hold for Federer, meaning Berdych will serve for the set.

Image source, Reuters

Roger Federer looks mega grumpy out there. He challenges a call on the baseline, and Hawk-Eye shows it's out. He frowns and slinks off as Berdych takes a 30-0 lead.

Berdych continues to play so beautiful shots and moves to within a game of taking the first set. They've only been playing for 25 minutes!

Mark Woodforde
Australian 12-time Grand Slam doubles champion on BBC Radio 5 live sports extra

It's been a bit untidy from Federer so far.

"Oooh," say the crowd, in a worried tone, as Federer double faults for 15-15.

Their concern doesn't last for long when he pulls out a trademark forehand down the line.

The two battle at the net - Federer poking lightly over and Berdych responding but shooting wide.

The defending champion holds.

Mark Woodforde
Australian 12-time Grand Slam doubles champion on BBC Radio 5 live sports extra

Image source, EPA

It's a sound start by Berdych. He has to serve well and land his first serves. There's already signs that Federer, trying to adjust the pace, has chipped his backhand return, and the ball sits up for Berdych. It allows him to take control of the point.

Having clocked up eight unforced errors in the early stages, ol' Rog has got his head in the game and has started to chomp away at Tomas Berdych's serve.

At 30-30, Federer goes for the drop shot into the corner to bring up break point... but he screws it up. It's gone over the mark. That wasn't pretty at all.

Berdych responds with an ace to hold.

A warm smattering of applause rings out around the Rod Laver Arena as Roger Federer finally gets off the mark in this first set.

He sends a storming forehand winner into the empty court for a hold to 15.

*denotes next server

Image source, Reuters

Berdych has come out all guns blazing - and it's containing the second seed.

The 32-year-old consolidates the break with a hold to 15 to take a healthy lead.

Russell Fuller
BBC tennis correspondent at Melbourne Park

Image source, Getty Images

Berdych is making this look easy tonight. He has such an easy power.

Huh. This is un-Federer like. He's coughed up a break point at the first opportunity.

The Swiss manages to rescue it with a decent second serve for deuce.

Berdych then gets a bit angst-ridden as the umpire has called his forehand long. The Czech reviews, and it was a good call from the chair.

On the second deuce, Federer slaps the net. Another break point for Berdych.

Federer sprays the ball wide. Who saw this coming? The defending champion is 2-0 down already.

Tomas Berdych loosens his shoulders and charges up his forehand to lead 40-15.

Roger Federer snaps back to claim another point off the 19th seed's serve but Berdych sees it out.

Let me know when you're ready to discuss the fact Berdych is wearing a backwards baseball cap at the age of 32.

Here we go then. Tomas Berdych gets us under way in this men's quarter-final.

The Czech world number 20 has reached a decent landmark in this match. I think this means he has to bring cake for everyone...

Image source, Getty Images

It was a Federer Special the last time these two met...

Federer and Berdych must be sick of the sight of each other in Melbourne.

The pair go head-to-head for the third successive Australian Open - their fifth in total - and Federer has won every time.

Berdych is hoping to end an eight-match losing streak against the world number one, which stretches back to 2013 in Dubai.

You have to go back to 2012 to remember the last time Berdych beat the Swiss in a Grand Slam.

Defending champion Federer is aiming to reach his 14th semi-final here, while Berdych goes for his third.

Image source, Getty Images