Daniel Kiernan
Former British tennis player

This where you want to be the server at the start of the third set.

You don't if you get broken, but if you keep holding serve then it keeps putting you in that position of always being slightly ahead. It applies a little bit of scoreboard pressure.

Right now, you can catch a return or get a couple of balls back deep, and all of a sudden Marino misses a couple of shots that she normally wouldn't have done, and then you are shaking hands.

Rebecca Marino looked to be in control of that rally, but it's the Canadian who makes the first mistake and sends the ball long.

A superb ace from Katie Boulter takes us to 30-30.

Oh dear. Katie Boulter is in deep, deep trouble here.

Two misses from the Briton open up a 0-30 lead for Rebecca Marino.

A wild mishit from Katie Boulter earns a couple of gasps on Kia Arena, and it isn't long before Rebecca Marino gets the hold to level the set.

That took just 69 seconds.

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Katie Boulter is one game away from the second round but can she do it right here, right now?

It's going to be a struggle. The Briton has hardly troubled Rebecca Marino on serve so far in this third set.

There's too much power on that forehand for Katie Boulter to deal with, but she takes a big breath before her next serve and Rebecca Marino can only find the net.

And there's the all-important hold for the British number one as Marino pushes into the net again.

"Oh Katie Boulter," chant the Melbourne crowd. You feel this is a must-win service game for Katie Boulter.

She's got off to a great start, flinging down a booming backhand for a 30-0 lead.

Daniel Kiernan
Former British tennis player

Maybe Katie Boulter loves a love story. Maybe she has looked into the box and seen Alex de Minaur. Maybe that is going to have an impact as well.

They are the Posh and Becks of the tennis world.

I saw the Great Britain Davis Cup coach look and smile at Alex de Minaur as if to say: "She wasn't hitting forehands like that before you got here."

We'd been lacking a bit on the ace front during the opening two sets, but both players are pulling them out of the bag now.

Two from Rebecca Marino there as she opens up a 40-15 lead before Katie Boulter finds the net.

Daniel Kiernan
Former British tennis player

I think Boulter is doing a great job mentally.

I don't think we can kid ourselves that this is her best tennis performance right now, but it is certainly showing the great competitor that she is.

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Yes! Smiles on the faces of Katie Boulter's mum and Alex de Minaur.

A much better service game for the British number one as she wraps it up with a fierce forehand winner. On we go.

Alex de Minaur has finished his warm-down and made his way to the Kia Arena to watch his fiancée Katie Boulter.

I fear this is going to be a nervous watch for him. And for us!

No stopping those. A brutal ace gets Rebecca Marino's service game up and running.

There's just no stopping the Canadian's momentum as she fires down another ace and races to a love hold.

Back to you, Katie.

Daniel Kiernan
Former British tennis player

I think Boulter is running out of ideas a little bit because the ball striking from Marino is pretty relentless right now. Hats off to Marino for the level she is bringing.

I was concerned about this match-up for Katie Boulter a little bit because they play very similarly and Marino is just doing it a little bit better right now.

What about that! Katie Boulter takes the sting out of Rebecca Marino's return and flings a forehand winner down the line in the opposite direction, pinching the line.

Marino goes long on the next one, and we hear that huge roar of relief from Boulter once again.

When she needs it most, the ace comes up clutch for Katie Boulter before she advances quickly to the net to dink over the next point. Deuce.

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A collective groan from the Melbourne crowd as Katie Boulter, who has rarely strayed from big baseline hitting, goes for a sneaky drop shot.

It fails to come off, and she's in real trouble now. Rebecca Marino has two break points.

Katie Boulter looks absolutely fuming as Rebecca Marino stands firm at the net to stop the Briton's passing shot.

And that won't help Boulter's fury either. The Canadian can't quite believe she's found the line there, but she has and that's the hold.

Daniel Kiernan
Former British tennis player

We have all been in one of these matches and, ultimately, Katie Boulter is just going to have to fight her way through this.

I don't think it's necessarily going to be beautiful and perfect tennis that is going to get her through this match, but she is going to have to dig her heels in and keep holding serve.

And she is going to have to hope that Rebecca Marino drops her level a little bit and drops a game or she wins a tie-break.

The pressure is back on Katie Boulter, who seems to be having some real difficulty on serve.

Or not! There's two aces from the British number one to bring up a 40-15 lead, and her next serve is big enough to pull Marino out wide and unable to deal with the next series of Boulter returns.

Much, much better.

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