Use play icon at top of page to listen to Radio 5 Live Sports Extra commentary (UK only)
Alexander Zverev beats Daniel Altmaier 7-6 (7-3) 6-1 7-6 (7-1)
World number one Ashleigh Barty hammers Lesia Tsurenko 6-0 6-0
GB's Cameron Norrie loses 6-3 6-0 6-4 to Sebastian Korda
Rafael Nadal into second round, beating Marcos Giron 6-1 6-4 6-2
Defending champion Naomi Osaka defeats Camila Osario 6-3 6-3
Nine-time champion Novak Djokovic absent after being deported
Day one of Australian Open from Melbourne Park
That's all for the text part of this page but press the play button at the top to listen to BBC Radio 5 Live Sports Extra commentary from the all-German match between third seed Alexander Zverev and Daniel Altmaier.
We'll be back at 04:00 GMT on Tuesday with a very busy day two for the British hopes.
Meanwhile, here are reports from today's action so far...
We have the schedule for tomorrow and it's a massive day for the Brits.
Andy Murray, a five-time finalist here, gets his campaign under way tomorrow with a tough-looking challenge against 21st seed Nikoloz Basilashvili of Georgia.
That one will be on John Cain Arena, starts at about 04:00 GMT on Tuesday and we will have live text commentary on this website.
That's a good court for British fans to have tickets for as Liam Broady takes on the always-entertaining Aussie Nick Kyrgios after the Murray match.
British qualifier Harriet Dart is the second match on Rod Laver Arena, taking on former French Open champion Iga Swiatek.
Britain's Emma Raducanu, who brilliantly won the US Open in September, is the last match of the day on Margaret Court Arena and plays American Sloane Stephens.
Heather Watson is third on court eight and she meets Egypt's Mayar Sherif, while Dan Evans, the 24th seed, is out on court 13 against Belgium's David Goffin.
Barty 6-0 6-1 Tsurenko
Barty was speaking to fellow Aussie Jelena Dokic on court, after the match.
"This is beautiful - it's felt like it's an eternity since I was back on this court. Playing as well as I did tonight it was a lot of fun out here.
"End to end I did a good job in adjusting but overall I felt like I enjoyed it and that's the most important thing.
"I'm a proud indiginous woman, I love to celebrate my heritage. It's what connects me me to all of you here, and what connects me to the land."
Image source, Getty ImagesBarty 6-0 6-1 Tsurenko
In the second round Ashleigh Barty will take on another qualifier as she meets Italian 23-year-old Lucia Bronzetti, the world number 145, after she beat Russia's Varvara Gracheva in the opening round.
Barty 6-0 6-1 Tsurenko
From 40-0 to 40-30 after Barty nets and misses with a slice, but the third match point is taken and the world number one wins in only 54 minutes.
Devastating and brilliant from the Australian.
Ashleigh Barty, aiming to be the first Australian to win here since 1978, cruises into round two.
Triple match point for Barty.
Barty 6-0 5-1 Tsurenko
Lesia Tsurenko does indeed avoid an embarrassing 6-0 6-0 defeat - saving two match points.
Now Barty is serving for a place in round two.
Ashleigh Barty, after a 20-shot rally, shows great variety to earn her second match point.
Tsurenko's first serve is out, Barty then nets and Tsurenko saves the match point. Deuce.
Match point for Barty.
#bbctennis
Rob Knapper: Can anything be more relaxing than listening to @gigi_salmon, external and the rest of the tennis team on tennis breakfast whilst working from home.
Georgie Heath: This Ash Barty domination makes the Aussie ashes performance look pretty tame.
Barty 6-0 5-0 Tsurenko*
Tsurenko was at 0-30 on the Barty serve but the Australian then wins four points in a row and it is almost over.
Tsurenko has to serve to stay in the match and see if she can get at least one game on the board.
*Barty 6-0 4-0 Tsurenko
Laura Robson
Former British number one on BBC Radio 5 Live
It's just not a fun situation [for Tsurenko] to be in. You don't want to let the crowd down, you don't want to let the team down, given that they are watching you on this huge stage.
*Barty 6-0 4-0 Tsurenko
Ashleigh Barty could meet reigning champion Naomi Osaka in round four and, if that happens, it will definitely be much tougher than this one.
Lesia Tsurenko sends a forehand into the net and that gives Barty a second break and she's now 6-0 4-0 ahead.
The easiest of opening rounds for the Australian.
Barty 6-0 3-0 Tsurenko*
Gigi Salmon
BBC Radio 5 Live Sports Extra tennis commentator at Melbourne Park
Barty just wants a clean match, firing, doesn't want to give a game away and put down a marker.
Keys 7-6 (7-2) 5-5 Kenin
Sofia Kenin, champion in 2020, is battling to stay in this year's tournament.
She's just broken Madison Keys as the American attempted to serve out their first-round encounter.
Barty 6-0 3-0 Tsurenko*
A hold to 15, in a game that included Barty's third ace of the match and Tsurenko's pain continues.
She might not even make it to an hour on court. Only 36 minutes played and the scoreboard is showing a 6-0 3-0 mauling.