Serena Williams defeats Ashleigh Barty 6-2 6-1
Novak Djokovic beats Lukas Lacko 6-3 7-6 (7-2) 6-1
Laura Robson & Heather Watson knocked out
Andy Murray plays Go Soeda on Tuesday
Piers Newbery
BBC Sport at Melbourne Park
"Boris Becker is sitting down below those of us in the media seats, sporting a sharp new haircut and tentatively trying out a few of the standard tennis coach moves - the encouraging nod, the energetic clap, the sympathetic shrug. We're yet to see any diving at the net, second serve aces or serve volleying from Djokovic though, so Boris must be quietly fuming."
Jeremy Bates
Former British number one on BBC Radio 5 live sports extra
"Lacko is showing incredible defiance. He had a few moments of crisis but he has served his way out of trouble, hit a couple of big forehands, and seems to be at ease in this big stadium. He's showing what he's capable of and playing his best tennis in this environment."
The crowd, and Djokovic, applaud as Lacko unleashes a cross-court winner to inch ahead to 40-15. In between points, the Djokovic fans scream "Nole! Nole!" to boost their man and whether that affected Lacko we will never truly know, but the Slovakian screws a forehand wide to let the defending champion back into the game. At deuce, Lacko has the crowd purring with a stonking backhand winner down the line and he then goes on to wrap up the game with an unreturnable serve. The Melbourne crowd warming to the man from Slovakia.
Last year Djokovic became the second man in the Open Era to reach three of the four Grand Slam finals in three successive calendar years. Who was the first? Answers at the end of this game. Rat-a-tat-tat - Djokovic races ahead to 40-0 and earns a hold to love with a simple forehand winner.
A quick hold means the answer to the quiz question can be revealed: it was Roger Federer, who reached three of the four major finals between 2006 and 2009.
David Law
BBC Radio 5 live sports extra commentator
"All credit to Lacko. He's giving the packed house their money's worth. That was the first time that Djokovic has looked in the direction of Becker."
Image source, Getty ImagesJeremy Bates
Former British number one on BBC Radio 5 live sports extra
"It's great that people like Becker and Lendl are prepared to commit themselves to coaching. They have lots of other things going on in their lives but they want to come back to the coalface after being out of it for so many years. The top four have so much going for them that they can attract guys of this stature."
Djokovic hasn't rummaged deep into his super-sized box of tricks in this match but he hasn't needed to. The rubber-legged defending champion squanders one break point - his lob bouncing beyond the baseline - and Lacko comes through to move to within a point of holding. But a canny Djokovic drop shot forces the game back to 40-40. From deuce to advantage, deuce to advantage we go until Lacko sees out the game, a fine serve leaving Djokovic flat footed.
Djokovic pinning Lacko behind the baseline with a series of brutal blows and Djokovic has the upper hand throughout this game. Lacko nets a backhand... Djokovic with a crosscourt winner... and the Serb is level.
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Lacko proving there's some steel underneath that laidback demeanour by dragging himself back into contention from 0-30 to 30-30. The Slovakian then glides towards the net and comes way from the tape with a winning volley. A backhand into the tape from Djokovic and Lacko, once more, is ahead.
If I were a cowboy I'd probably yee-haw before describing a fabulous backhand winner from Lacko for 15-15, but I'm not so I'll keep it low key. Djokovic is more than capable of producing sizzlers from the baseline himself, however, and he does so on the next point, turning defence into attack with a punchy forehand winner. The Serb is able to absorb whatever Lacko throws at him. A wayward return from Lacko and the game belongs to Djokovic.
Djokovic yet to ask any questions of the Lacko serve in the second set and the world number 96 nudges ahead.
Alistair Bruce-Ball
BBC Radio 5 live sports extra commentator
Image source, Getty ImagesNot a bad spot to watch the Aussie Open tennis if you haven't got a ticket for the show courts.
Djokovic, content to remain on the baseline, is targeting the Lacko backhand but the Slovakian holds firm and it's the Serb who crumbles like a chocolate flake, plonking a forehand into the tape. A cheeky trick shot from Lacko, who twirls his racquet behind his back to get the ball back in play. Djokovic smiles at the Slovakian's ingenuity, but remains ruthless - stepping in with a punchy forehand winner. Despite the circus tricks, it's a trouble-free hold for Djokovic.
Roars from the crowd as they witness Djokovic, scampering across the baseline, thump over a winning crosscourt backhand. The ball clipped the net on its way to the corner and the Serb raises his arm to acknowledge that there was a touch of good fortune involved in that winner. It's the only point Djokovic wins as the world number 96 holds to 15.
A fine hold by Djokovic - an ace and a drop shot are thrown into what is called the mixer - and it seems unlikely that we will witness an upset on Rod Laver this evening.
Whoever is in charge of the TV pictures seems to be more concerned with happenings on Hisense Arena where home boy Jordan Thompson is 2-1 up on the big serving Jerzy Janowicz, though the Pole is leading 4-1 in the fourth set.
And sixth seed Petra Kvitova is out after suffering a 6-2 1-6 6-4 defeat by Thailand's Luksika Kumkhum, the world number 88.
Back on Rod Laver Arena, Lacko throws an ace out to the wings to secure the first game of the second set.
Jeremy Bates
Former British number one on BBC Radio 5 live sports extra
"That's a very impressive start from Djokovic. There was a slight bit of pressure having lost his serve but he stepped it up. He looks in terrific shape, is moving superbly around the court, and trying to attack with the freedom of a Roger Federer."
There were a few iffy moments for the defending champion, but Boris Becker will surely be pleased with how the Serbian worked his way through the opening set. Lacko directs a lob long and the first set belongs to Djokovic.
A Lacko forehand goes long and Djokovic is upping the ante, grabbing two break points to earn a chance to serve for the set.
The Djokovic backhand malfunctioning and the Serb needs to reboot quickly as Lacko gains two break points. Loose and wild from Djokovic and the underdog is back on par.