David Law
Radio 5 live sports extra commentator at Melbourne Park

Thought it might go the other way when Federer got into his spat with the umpire, but no. Energised him. He’s realised Berdych is nailing it, so he’s started with the variety. Dropshot winner on set point.

Roger Federer gets himself out of a bind, drifting from left to right with the greatest of ease to see out his service game and avoid the threat of a break.

These two are enjoying sending each other across the court, back and forth.

After an aesthetically pleasing 19-shot rally, Federer stays light on his feet to come out on top.

He finds a backhand winner for a 40-30 lead. But then he nets so we go to deuce.

Another net gives Berdych a break opportunity. That is taken away from him by a straight backhand down the line. Back to deuce.

Berdych stays cool, despite at one stage being out-witted by Federer drop shot, to hold and get off the mark in the second set.

Dennis Ethan: Amazing how Federer's backhand is doing the business and not the forehand. Gotta let that sink in.

Image source, EPA

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

Tennis players have egos. The crowd are willing Federer on, there's almost applause for a missed return for Berdych - it must get to players. He's made to be like a little mouse against the greatness of Federer.

Federer comes through a safe hold to 15, seeing it out with a pulsating forehand.

He means business now.

Gigi Salmon
Radio 5 live sports extra commentator at Melbourne Park

When Federer got the break back, I think a little part of me thought that was game, set and match. I know that sounds negative but it felt like the first set was so important fro Berdych mentally. My hopes slipped away for him.

Tomas Berdych was 5-2 up. He's just lost the set.

He's gone to his seat to let that sink in for a minute.

Image source, AFP

How has Roger Federer done that?!

A drop shot drips just over the net, a sprawling Tomas Berdych can't get to it, and the first set goes Federer's way.

Federer's power play is coming out.

Berdych is overwhelmed by his opponent and nets for 5-1.

Then the second seed sends down an ace. It was called in, Berdych thinks it's out - and he's right! Second serve.

Federer then sends Berdych running all over the court. The Czech does so well to retrieve the ball but eventually he's outdone.

Five set points to Federer.

Image source, Getty Images

Forward comes Berdych, and he gets his first point of the tie-break as Federer hurries a backhand into the net.

Too much space there, though, and Berdych whips a forehand long.

Federer comes storming into the net to volley over. Berdych tries to lob it back over on the backhand but it's long.

The defending champion approaches the net again and finishes with finesse. He leads 3-0.

Tomas Berdych will serve to get the tie-break going.

What a shot! Roger Federer flicks an uppity forehand right onto the baseline! Berdych challenges but he's absolutely nailed it.

Grumpy Fed slams down at the net to hold. Into a tie-break we go...

Russell Fuller
BBC tennis correspondent at Melbourne Park

We're seeing sarky Fed tonight!

Well now, we do have a grumpy Federer on our hands.

The ratty Swiss mutters something to the chair about challenges, and not having any left. The crowd laugh. He does not.

In the meantime, he goes from 30-0 up to 30-40 down.

Berdych plays it safe in a long rally before biting on a backhand. It's over the line and the break opportunity goes to waste.

Image source, AFP

Ooof, this is a battle now.

Berdych scoops his body down low and outsmarts his opponent for a 40-0 lead.

And Federer slaps the net to hand a love hold to the Czech.

*denotes next server

An ace from Federer is followed by a forehand volley that Tomas Berdych, lurking behind the baseline, can't get bear.

Long goes the Berdych backhand and, in the blink of an eye, Federer holds to love.