Russell Fuller
BBC tennis correspondent on BBC Radio 5 Sports Extra

Arthur Gea is now crouching down, you can't have a medical timeout for cramping.

It's not yet taken over his entire body, so he's still just about in this match.

Arthur Gea opens his racquet face and sprays a forehand winner into the corner to level the scores.

However, he's feeling his calf after the point and does a bit of stretching. You really don't want cramp to set in now.

He nets a down the line forward following a tame second serve. Advantage Stan Wawrinka.

We're going to a decider.

Sorana Cirstea has had to be stubborn and dig in her heels, but it's been worth it and she gets the all-important break to stay in this tie.

Stan Wawrinka gets on the board with an ace.

Arthur Gea, who has twice served to stay in the match, holds to 15.

After more than four hours and 20 minutes, we're heading to a fifth-set tie-break.

First to 10 will go through. Will it be Stan Wawrinka - the former champion and 40-year-old wildcard in his final Australian Open - or Arthur Gea, the qualifier in his first Grand Slam?

Now then! Are we going to a decider?

Sorana Cirstea has two set points to take us to a third.

Naomi Osaka looks at the baseline in confusion. She thought that was going long from Sorana Cirstea, but it just pinches the paintwork.

The former world number one can't quite find the same accuracy, missing a couple of simple groundstrokes as Cirstea holds to love.

Osaka will now serve to stay in the second set. What can Cirstea do here?

Image source, Getty Images

Ace number 12 from Jannik Sinner gets the defending champion off to the ideal start, but James Duckworth hits back with a volley for 15-15 after putting his opponent on the back foot.

Duckworth holds his hands on his head after narrowly missing the line - and with it his chance of potentially salvaging the set disappears.

Sinner is one set away from the third round!

Stan Wawrinka starts the 11th game of the fifth set with an ace and finishes it with a serve winner down the T.

A hold to love.

The pressure is back on Arthur Gea.

Sorana Cirstea had the whole court to aim for to bring up a break point but she whacks her forehand long and Naomi Osaka ticks off another hold.

Arthur Gea is equal to the pressure.

Ace, a long return, and a cross-court forehand winner see him race into a 40-0 lead.

Stan Wawrinka's attempted drop shot goes into the net to complete a routine hold to 15.

Image source, Getty Images

This set started really positively for James Duckworth, and remained so for six games.

It looks as though this one, too, will get away from him - but he at least ensures Jannik Sinner must serve out for a two-set lead.

Two unforced errors see the opportunity slip for Naomi Osaka and Sorana Cirstea steps it up from there, adding a bit more pace to her serve to halt the four-time Grand Slam champion's momentum.

Stan Wawrinka sits wrapped in a towel, closes his eyes, and takes a deep breath.

The umpire calls "time" and he jogs over to his mark, whipping up the crowd with his arms.

Arthur Gea is serving to stay in the match.

A rare double fault by Jannik Sinner gives James Duckworth a head-start, but the Italian soon makes amends.

A delicious sliced drop shot gets him to game point, before Duckworth is forced into the net following a hefty first serve.

Cool as a cucumber from Stan Wawrinka, securing the hold to love with a teasing forehand drop shot.

He is one game away from a marathon win and a spot in round three.

Over to you, Arthur Gea.

Naomi Osaka is trying to step up her level here and two winners fly off her racquet to give her an opening at 0-30.

Sorana Cirstea replies with a winner of her own but then finds the fence and offers a big chance to Osaka.

Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 Sports Extra and BBC Sounds

Arthur Gea hasn't really missed a beat in this game.

Even though he's missing that first serve, he's handling the situation as if he's been here several times.

Image source, AFP via Getty Images

He came from 15-40 down and saved four break points before sealing the game in style with a deft forehand volley angled across the net. Arthur Gea HOLDS.

Smart play from Naomi Osaka, who sees Sorana Cirstea going one way and then sends the ball back the other despite there being less space to play with.

The Japanese 16th seed wraps up the hold and we stay on serve in this second set.