Day five of the Australian Open
Use audio icon to listen to BBC Radio 5 Sports Extra commentary (UK only) of Jasmine Paolini v Renata Zarazua
Defending champion Jannik Sinner beats world number 173 Tristan Schoolkate 4-6 6-4 6-1 6-3
GB's Katie Boulter loses 7-6 (7-3) 2-6 6-2 to Veronika Kudermetova in second round
Emma Raducanu wins 6-3 7-5 against Amanda Anisimova to reach third round for first time
*Sinner 4-6 6-4 2-0 Schoolkate
Ryan Harrison
Former American tennis player on BBC Radio 5 Live and BBC Sounds
You don't expect to see Jannik Sinner dropping sets this early on but as we've always known it there is a time and a place to maybe get the top players in not their best form and sometimes it's those early rounds when you can see that happening.
*Sinner 4-6 6-4 2-0 Schoolkate
Tristan Schoolkate's energy has changed, too. The Australian is looking pretty dejected as Jannik Sinner brings up two break points.
Schoolkate saves the first, but he goes long on the second.
This feels like this match is heading in one direction only.
Sinner 4-6 6-4 1-0 Schoolkate*
It's all gone a bit quiet on Rod Laver Arena as momentum has shifted in favour of Jannik Sinner.
Australia's Tristan Schoolkate looks like he's able to challenge Sinner on serve, but the Italian moves through the gears and gets it over the line.
Kudermetova 7-6 (7-3) 2-6 6-2 Boulter
Russell Fuller
Tennis correspondent on BBC Radio 5 Sports Extra and BBC Sounds
It was a little bit puzzling I thought in that third set because apart from those first six games, you really thought Katie Boulter was the better player, regularly making inroads on the serve of Veronika Kudermetova who did play a really good third set.
Image source, Reuters*Sinner 4-6 6-4 1-0 Schoolkate
Tristan Schoolkate had surprised us all by taking that opening set, but it looks like Jannik Sinner has found his rhythm and there's a danger that he could storm through this match now.
The defending champion gets the early break.
Kudermetova 7-6 (7-3) 2-6 6-2 Boulter
Got it!
Katie Boulter's second serve wasn't her best and Veronika Kudermetova capitalised with a powerful forehand.
A rollercoaster match but Kudermetova had the momentum in the deciding set and she's run away with it in the end.
Disappointment for Boulter, she misses the chance to progress to the Australian Open third round for the first time in her career.
Kudermetova 7-6 (7-3) 2-6 5-2 Boulter*
Abigail Johnson
Commentator on BBC Radio 5 Sports Extra and BBC Sounds
Veronika Kudermetova has had dips and rises throughout this match but she looks sure of herself.
Kudermetova 7-6 (7-3) 2-6 5-2 Boulter*
A huge backhand winner from Veronika Kudermetova brings up two match points.
Katie Boulter misses her first serve on the first...
Sinner 4-6 6-4 0-0 Schoolkate*
Jannik Sinner scratches his head. He's not having the best of days and it looks like he's at a loss as Tristan Schoolkate pulls level at 30-30.
But even on bad days, top players pull through and Sinner manages to hold serve and take the second set.
We're all square.
Kudermetova 7-6 (7-3) 2-6 5-2 Boulter*
Abigail Johnson
Commentator on BBC Radio 5 Sports Extra and BBC Sounds
It's getting real for Katie Boulter who can barely afford a foot wrong now under the lights.
Kudermetova 7-6 (7-3) 2-6 5-2 Boulter*
Katie Boulter produces an ace at a crucial moment.
Veronika Kudermetova was not happy with that, she thought it had gone out but the hawk-eye shows it was in by a millimetre.
Kudermetova 7-6 (7-3) 2-6 5-2 Boulter*
The crowd appear to be trying to lift Katie Boulter's spirits as she serves to stay in the match and, in turn, the tournament.
She drops her head as Veronika Kudermetova whizzes a forehand past her.
Kudermetova 7-6 (7-3) 2-6 5-2 Boulter*
Leon Smith
GB Davis Cup captain on BBC Radio 5 Live and BBC Sounds
This is maybe the first signs of a little bit of fatigue, there have been a couple of brutal rallies for Katie Boulter, she has covered so much ground and that was the first time her feet just got a little bit stuck.
Kudermetova 7-6 (7-3) 2-6 5-2 Boulter*
Veronika Kudermetova consolidates that break of serve and all of a sudden things are looking glum for Katie Boulter.
A no-nonsense hold to love from the Russian leaves Boulter serving to stay in the set.
*Kudermetova 7-6 (7-3) 2-6 4-2 Boulter
Abigail Johnson
Commentator on BBC Radio 5 Sports Extra and BBC Sounds
Katie Boulter is straining her arms and yelling at her team in frustration here as she goes down on the board.
*Kudermetova 7-6 (7-3) 2-6 4-2 Boulter
Veronika Kudermetova has the advantage!
Just like in set one, Katie Boulter is going to have to come from behind if she wants to win this match.
A big moment in the match as the Russian takes the break at the first opportunity.
*Sinner 4-6 5-4 Schoolkate
Not just yet, Jannik. Tristan Schoolkate rushes to the net to smash down an overhead and hold serve.
Sinner 4-6 5-3 Schoolkate*
Three games in a row for Jannik Sinner and now he's got the chance to break Tristan Schoolkate again to win the second set and level this second-round tie.
Kudermetova 7-6 (7-3) 2-6 3-2 Boulter*
We've just gone past the two-hour mark as Katie Boulter misses the chance to earn a couple of break points with a forehand into the net.
Veronika Kudermetova forces the error from Boulter with a powerful serve to take the hold.
*Sinner 4-6 4-3 Schoolkate
It was coming. Jannik Sinner steps it up a gear, and he gets his reward.
Tristan Schoolkate had no chance of saving that break point with a blistering forehand from the world number one.