Thunderous from Kyle Edmund, pushing Grigor Dimitrov into the corner of the court, but Dimitrov responds with a gorgeous passing shot of his own.

Edmund gets himself to 30-30 with another blasting forehand, but an error on the baseline hands Dimitrov a break point.

A smash from Edmund will take us to deuce. Edmund mutters that he "heard something" to the umpire - Dimitrov looked a little unhappy about something too.

Piers Newbery
BBC Sport at Melbourne Park

The hum of chatter fills the arena, the buzz of an upset bringing the afternoon to life as Edmund announces himself to the locals, who might not have been following his progress too closely up until now.

Edmund's forehand and serve make quite an impact - the brutal service return winner to break serve at 4-4 drew as many laughs as gasps, it was so big - and even Sir Tim in the front row was moved to applaud one sharp backhand volley winner.

Now then, how important will that be?

A thumping, cross court winner from Grigor Dimitrov, and he fends off Edmund's challenge to hold serve.

Image source, AFP

Into the net goes Kyle Edmund, and the first break point goes begging, before the Brit errs on the backhand.

Good second serve from Dimitrov! It's deuce.

Two-handed backhand from Kyle Edmund and he places it beautifully, the ball curving down the line.

A scrappy service game from Dimitrov, and he's gifted Edmund three break points to boot...

Dominic Inglot
British doubles player on Radio 5 live at Melbourne Park

Credit to Dimitrov, he's really found his range on his slice now. He's going very low and short, occasionally throwing it down the line to catch Edmund off guard.

Too loopy and too rushed from Kyle Edmund, and his forehand goes sailing out the baseline.

There's a loud shout of "come on!" from Dimitrov as he gets the first break.

A good serve out wide from Kyle Edmund but he's drawn into a rally and Grigor Dimitrov, slicing from wide to his right, draws the error out of Edmund's forehand.

Edmund's coach, Fredrik Rosengren, gives his charge the look of a disapproving father, but another forehand down the line goes awry to hand Dimitrov a break point.

Excellent retrieving from Kyle Edmund as he keeps making Dimitrov play an extra shot but the Bulgarian is finally able to put a smash away. An ace seals a love hold for the world number three.

That'll be the first set to Kyle Edmund!

Fine work from the Brit - he saved three break points and then took advantage of a bit of frustration from Grigor Dimitrov to get himself ahead in this match. He clenches his fist and raises it towards his box in a muted celebration.

Image source, Reuters

Set point number two, as Dimitrov errs once again...

Set point to Kyle Edmund! A frustrated Grigor Dimitrov bashes his return into the net.

But Grigor Dimitrov is like a hamster on a wheel behind that baseline. He races up and down, eventually drawing the error out of Edmund.

Lovely from Grigor Dimitrov, pushing Kyle Edmund further and further into the corner of the court, before he comes hopping forward to tonk a forehand over.

A cracking serve saves Edmund, though. Deuce number two.

Image source, Getty Images

A 190kph serve saves the first break point.

And an overhit return from Grigor Dimitrov saves the other!

Dominic Inglot
British doubles player on Radio 5 live at Melbourne Park

They are both looking a little tentative.

What happened there?! Kyle Edmund gets up to the net, goes for a swat and ends up missing the ball, which brushes his shirt sleeve and trickles behind him.

Grigor Dimitrov, shrouded in shade at the back of the court, slaps a return long, but it's the Bulgarian who comes out on top in the tussle of the forehands. Two break points to Dimitrov.

Dominic Inglot
British doubles player on Radio 5 live at Melbourne Park

126kph second serve - taking nothing away from Kyle - there is nothing on it. Dimitrov, that's where his problem is. He is feeling the heat. There have been a couple of times Kyle has run around it and taken it to the cleaners.

Fine work from Kyle Edmund there - he launched into Grigor Dimitrov's second serve.

Now, to try and serve it out...

Ooft! Kyle Edmund sets Grigor Dimitrov up and goes for the big forehand, but the ball drifts just over the baseline. That's the first break point saved.

Not the second, though! That's superb from Edmund - he goes darting very far to the left to pick up Dimitrov's serve early, and then smashes his forehand past his opponent in response.

Edmund will serve for the first set!

A lovely backhand down the line from Edmund has Dimitrov slapping the ball into the net.

Another double fault from Dimitrov hands Edmund a way in, and a rushed forehand from Dimitrov brings up two break points...