It all feels a bit flat on Rod Laver Arena now.

There are groans from the crowd as Emma Raducanu goes big with a forehand that flies well wide. It allows Coco Gauff to ease clear on serve and a love hold backs up the break for the American.

CoCo Vandeweghe
Two-time Grand Slam semi-finalist on Radio 5 Sports Extra

The last rallies have been very long and that does weigh on you in the later stages of the set.

We can all feel the tension building.

Emma Raducanu saves a second break point with a clever, low hit from the baseline that doesn't bounce up high enough for Coco Gauff to salvage.

The problems with Raducanu's serving continue, however. A second double fault of the game costs her the break and Gauff is in control of this now.

The quality level has generally gone up at the start of the second set, but a double fault from Emma Raducanu puts her under serious pressure.

Three break points for Coco Gauff.

Coco Gauff secures the hold following an enthralling rally, which ends with Emma Raducanu dropping a backhand into the net. No early breakthrough for the Briton, for now at least.

CoCo Vandeweghe
Two-time Grand Slam semi-finalist on Radio 5 Sports Extra

Emma's unforced errors are just too high. That has to be cut down because she can't let Coco dictate. She came out of the changeover way early - talking to her box and seeing if the game plan is working.

This doesn't feel like a second round match. There's a tension in the atmosphere that suggests there's much more on the line than a third round spot - and I'm sure we won't be waiting long before that is the case when these two young stars meet at future Slams.

Emma Raducanu is finding her rhythm now and reaches 30-30 on the Coco Gauff serve.

The players patiently wait for members of the crowd to find their seats.

It's Emma Raducanu serving first in the second set and she makes a solid start, a quick one-two punch taking her to 40-0 before Coco Gauff nets a return.

Up and running.

Jonathan Jurejko
BBC Sport at Melbourne Park

The visceral and throat-burning roar which comes from Coco Gauff at the end of the set signifies how much she is being tested here.

Russell Fuller
Tennis correspondent at Melbourne Park

This is going broadly as I thought it would. Raducanu hasn't had enough matches in the legs.

Even though she is older, there is quite a gulf in experience between them.

Very entertaining but Gauff is being made to work extremely hard.

Jonathan Jurejko
BBC Sport at Melbourne Park

"Come on Emma, you're from Bromley!" shouts one male fan with a Kent accent.

Not exactly sure what that means or what qualities people from Bromley are supposed to possess...

A second set point for Gauff - and this time she gets it as Raducanu nets a return.

So nearly for Raducanu, with three break points passing her by in that final game, but now she must come from a set behind against the world number seven.

CoCo Vandeweghe
Two-time Grand Slam semi-finalist on Radio 5 Sports Extra

That rally had every shot in the book. A real quad-burner!

Again Coco Gauff rescues herself, and now the American can finally have a look at a set point...

But a superb, rapid return from Emma Raducanu hauls her back to deuce.

Coco Gauff is hanging on in this game.

Break point number three arrives for Emma Raducanu, who turns to her team and clenches her fist.

Another excellent Coco Gauff backhand takes the American to deuce, but Emma Raducanu will have a second chance to break as, slightly fortuitously, she beats Gauff at the net.

A big point at 30-30, and it's Emma Raducanu who holds her nerve.

Coco Gauff overhits a backhand. Break point Raducanu!

Jonathan Jurejko
BBC Sport at Melbourne Park

The Brits always receive loads of support from the expats in the Melbourne crowds, but I'd say the shouts of encouragement on Laver tonight are quite evenly split.

That's testament to the popularity of Gauff, who endeared herself to many around the world with that famous run to the Wimbledon last 16 as a 15-year-old in 2019.

CoCo Vandeweghe
Two-time Grand Slam semi-finalist on Radio 5 Sports Extra

Emma has to lock in here and make lots of returns and at least get those break point chances on Coco's serve.

Now, can Emma Raducanu trouble Coco Gauff? She has nothing to lose here. A missed forehand relieves some tension for Gauff but good returning from Raducanu keeps her close.