Briton Harriet Dart wins final-set tie-break to beat Misaki Doi & reach second round
GB's Johanna Konta, Kyle Edmund, Cameron Norrie & Katie Boulter all beaten
Rafael Nadal, Danill Medvedev, Nick Kyrgios into second round
Simona Halep & Karolina Pliskova advance but Maria Sharapova loses
Heather Watson's match pushed back to Wednesday
Day two of Australian Open in Melbourne
Listen to Tennis Breakfast on BBC Radio 5 Live Sports Extra - press play button at top of page
BBC Radio 5 Live Sports Extra
Stick with 5 Live Sports Extra as they bring you the rest of the action from Melbourne Park.
We're ending this live text here but there's still plenty of play to come.
Nick Kyrgios, Simona Halep, Daniil Medvedev and Alexander Zverev are all in action, along with Brits Cameron Norrie and Harriet Dart.
Sinner 7-6 (7-2) 6-2 6-4 Purcell
Image source, EPAHe swapped skis for a tennis racquet and now teenager Jannik Sinner is attracting the attention of one of the sport's greats at the Australian Open.
The 18-year-old Italian beat Australian Max Purcell 7-6 (7-2) 6-2 6-4 earlier to reach the second round of a Grand Slam for the first time, following praise from Roger Federer.
The Swiss has backed Sinner and says "we'll see so much more from him".
"He has great footwork for a big guy, because we forget how tall he is," said Federer, who along with Spanish world number one Rafael Nadal has hit with 6ft 2in (1.88m) Sinner in Melbourne.
"He can play like most of the best movers in the game right now, he can also play open stance and closed stance, which I think is a huge advantage for movement for the future."
Sinner was a competitive junior skier but switched his focus to tennis five years ago and says he is still learning.
"What he said is nice for me. But we still have to work," said Sinner.
It's been well over 24 hours since the Australian Open started and I *still* can't stop thinking about this Grigor Dimitrov kit.
I mean... what is it?!
Image source, Getty ImagesBritain's Cameron Norrie has just begun his Australian Open campaign - he's on serve in his match against France's Pierre-Hugues Herbert.
Up next on Melbourne Arena is Nick Kyrgios, while Simona Halep and Daniil Medvedev are already under way on the big two courts.
Svitolina 6-4 7-5 Boulter
Judy Murray
Tennis coach at Melbourne Park on BBC Radio 5 live sports extra
Very, very encouraging performance from Boulter. It was a tough draw. She had runs of really good play where she dictated but a lack of match fitness led to a run of errors but from where she has come from, I think her team will be pleased with that performance.
Svitolina 6-4 7-5 Boulter
There were some positive signs for Katie Boutler, especially after such a long time out with a back injury, but Elina Svitolina was able to find another level in the big moments.
Svitolina will play America's Lauren Davis next.
Svitolina 6-4 7-5 Boulter
There's no stopping that, though!
Elina Svitolina passes Katie Boutler with a lovely backhand and the fifth seed is through to the second round in straight sets.
Svitolina 6-4 6-5 Boulter*
A shank from Svitolina...
One match point saved.
Svitolina 6-4 6-5 Boulter*
Not ideal for the Brit as she double faults first up, but she's on the board with a lovely forehand down the line.
Flat hitting from Svitolina though, powering through her shots, and she gets herself two match points as Boutler's forehand finds the top of the net...
Svitolina 6-4 6-5 Boulter*
Right then, here's Katie Boulter, serving to take this match to a tie-break...
Svitolina 6-4 6-5 Boulter*
Svitolina races to 40-0 and though Boulter gets on the board, a backhand into the net from the Brit means she needs to hold again to stay alive.
*Svitolina 6-4 5-5 Boulter
Boulter still needs to hold serve to stay in the match and a superb backhand down the line from Svitolina gives her the first point of the game. But the Brit isn't daunted and a fabulous forehand takes her to 40-15. And an ace seals the hold. 5-5 in the second set now and Boulter is back in this.
Judy Murray
Tennis coach at Melbourne Park on BBC Radio 5 live sports extra
That was a great game from Boulter. There were two points where she caught Svitolina out with the short ball. Now she has the wind behind so there are possibilities here with her serve.
Svitolina 6-4 5-4 Boulter*
What a shot to break back with!
Some superb returns of serve have given Katie Boulter a footing in this game, and she lobs Elina Svitolina to perfection to break to love.
*Svitolina 6-4 5-3 Boulter
Shot! Elina Svitolina leaves Katie Boulter with a bit too much open space and the Brit slides a winner down the line for a 0-30 lead.
Now then! Svitolina sputters a drop shot into the foot of the net and Katie Boulter has three break back points.
*Svitolina 6-4 5-3 Boulter
A couple of wayward shots from Elina Svitolina, who may have allowed her mind to drift towards the second round, and she hands Boulter game point as a lob sails long.
Svitolina aims cross-court, misses, and the Ukrainian will have to serve this one out.
Svitolina 6-4 5-2 Boulter*
David Law
BBC Radio 5 Live Sports Extra tennis commentator
6-4 5-2 doesn't really tell the story of this match.
Svitolina 6-4 5-2 Boulter*
Katie Boulter misses a backhand and slaps it into the side of the umpire's chair, and some tired-looking errors from the Brit helps Elina Svitolina hold to 30.
Boulter will be serving to stay in the match.
*Svitolina 6-4 4-2 Boulter
Down the line aims Katie Boulter - and misses!
That might be it...
Svitolina 6-4 3-2 Boulter*
Katie Boulter picks an excellent time to swing down her first ace of the match, but Elina Svitolina won't go down that easily and she hammers away a winner to take us to deuce.
That's a brilliant return from Svitolina, picking up a wide Boulter forehand and a surprised Boulter nets.
Another break point...