ROD LAVER ARENA
Paula Badosa (ESP) defeated Petra Kvitova (CZE)  7-5 7-5
Ash Barty (AUS)  defeated Polona Hercog (SVN) 6-1 6-4
Novak Djokovic (SRB) [2 defeated Tatsuma Ito (JPN) 6-1 6-4 6-2
From 7pm AEDT: Tamara Zidansek (SVN) vs Serena Williams (USA) 
Filip Krajinovic (SRB) vs Roger Federer (CHE) 
MARGARET COURT ARENA
Naomi Osaka (JPN)  defeated Saisai Zheng (CHN) 6-2 6-4
Caroline Wozniacki (DNK) defeated Dayana Yastremska (UKR)  7-5 7-5
Tommy Paul (USA) vs Grigor Dimitrov (BGR) 
From 7pm AEDT: Jordan Thompson (AUS) vs Fabio Fognini (ITA) 
Madison Keys (USA)  vs Arantxa Rus (NLD)
Julia Goerges (GER) defeated Petra Martic (HRV)  4-6 6-3 7-5
Cori Gauff (USA) defeated Sorana Cirstea (ROU) 4-6 6-3 7-5
Stefanos Tsitsipas (GRC)  defeated Philipp Kohlschreiber* (GER) *retired
Hubert Hurkacz (POL)  vs John Millman (AUS)
Tennys' shock upset
Unseeded American Tennys Sandgren has pulled off a shock second round upset by knocking off eighth seed Matteo Berrettini in a thrilling five-set duel.
Sandgren who made the quarter-finals in 2018 raced out to grab a two sets to love lead before Berrettini fought back to force a deciding fifth set.
A back and forth slog unfolded before Sandgren emerged victorious with the 7-6, 6-4, 4-6, 2-6, 7-5 victory.
He'll now take on fellow American Sam Querrey in the third round.
Salty war of words erupts at Australian Open
Caroline Wozniacki's extended her career to the third round of the Australian Open with a rollercoaster win over Ukrainian Dayana Yastremska – but her impressive win was overshadowed by a salty war of words with the woman she eliminated.
Wozniacki prevailed 7-5 7-5 after fighting back from 5-1 down in the first set in a battle that see-sawed back and forth.
The former Australian Open champion was cleary left furious by the moment Yastremska took a medical time out from completely out of the blue, just as she was about to have to serve to stay in the match at 5-4 in the second set.
The WTA Tour physiotherapist came onto the court to treat Yastremska, forcing a delay of several minutes.
Yastremska had some strapping placed on her left thigh, but appeared to be moving freely when play resumed.
Wozniacki was able to keep her cool, despite being frustrated by Yastemska's tactic and eventually closed out the match a few minutes later with another break of serve.
Yastremska has developed a reputation for using medical timeouts as a tactic to unsettle her opponent – and Wozniacki was happy to call it out in her post match press conference.
"Obviously she tried to break my rhythm," Wozniacki said.
"And at 5-4 I don't think there is anything wrong. She was running just fine. So that's a trick that she's done before, and I knew that it was coming. But I was just trying to stay focused."
According to a report on Twitter from New York Times tennis expert Ben Rothenberg, Yastremska did not react kindly when told that Wozniacki had criticised her in an earlier press conference.
US teen's 30-year Grand Slam first
Teen sensation Cori Gauff completed a remarkable comeback victory after an epic battle against Romanian Sorana Cirstea on Melbourne Arena.
The 15-year-old US star, who defeated Venus Williams in the first round of the tournament, lost the opening set 4-6.
However, Gauff immediately recovered and raced to 3-0 lead in the second set, eventually tying the scores by winning the set 6-3.
Cirstea struck first blood in the decisive third set, breaking serve early to lead 3-0. Remarkably, Gauff won the following three games to tie up the scores once again.
The drama continued after Cirstea held up her hand during Gauff's serve, visibly irritating the US teen, who began aggressively fistpumping every point, directing the celebration at her Romanian opponent.
Guaff broke serve late, winning the final set 7-5, the packed crowd immediately rising to their feet for the 15-year-old.
The victory pushes her into the third round, making it three straight Grand Slams where she has advanced that far. Making her the first US woman to achieve the feat in 30 years.
She will face World No. 3 Naomi Osaka in the third round.
Barty's 32-year first
Ash Barty is through to the third round, becoming the first Aussie woman to do so in four consecutive Australian Open tournaments since 1988.
Barty started her second round match emphatically, breaking Slovenian Polona Hercog's serve to take an early 3-0 lead.
At Rod Laver Arena, the home crowd was right behind the Aussie hero, who is chasing the home nation's first Australian Open singles title in 42 years.
Barty dominated the remainder of the opening set, which lasted 24 minutes, winning 92% of points on her first serve, while Hercog can only manage 44%. The World No. 1 also chipped in with three aces.
Hercog didn't help her own cause, giving away three double faults in the opening set. The Slovenian is ranked the world No. 48, and has never faced Barty in a professional match before.
Hercog fought back during a gritty second set, holding serve more regularly to keep the match alive.
Unforced errors began creeping into Barty's game as the match approached the hour mark.
Barty survived a massive scare at 3-4, winning three break points to keep the second set in the balance.
Then, during a quick shift in momentum, Barty broke serve to take a 5-4 lead, closing in on a straight set victory.
Hercog earned another two break points the very next game, but Barty definitely ended the match with four consecutive points.
Aus Open takes seriously wild turn
Strong winds have impeded the Australian Open, the difficult conditions starting to get on No. 3 seed Naomi Osaka's nerves.
Last year's Australian Open champion won her opening set against China's Zhang Saisai at Margaret Court Arena.
However, as the winds started impacting gameplay, Osaka's consistency faded, and trailed in the second set 4-2 after Zhang broke serve twice.
At one point, Osaka threw her racquet on the ground and kicked it in frustration.
Winds in Melbourne were measured at 95km/h this morning and Osaka wasn't the only one struggling.
Osaka eventually prevailed though, bouncing back by winning four consecutive games and claiming the second round match in straight sets.
After the match, and interviewer asked Osaka about her chances of reclaiming the No. 1 title, but the Japanese star was quick to point out that is not possible ths tournament.
Australia's Astra Sharma was unable to win a game in her opening set against Estonian Anett Kontaveit, which lasted just 19 minutes. She eventually lost to the No. 28 seed in straight sets after making 28 unforced errors.
Seed No. 7 Petra Kvitova broke serve late to claim the opening set against Spain's Paul Badosa on Rod Laver Arena. In a tightly-contested match, Kvitova went on to win in straight sets 7-5 7-5.
Legend's brave Kyrgios claim
Tennis legend Jim Courier believes Nick Kyrgios could topple world No. 1 Rafael Nadal is they face off in the Australian Open.
Kyrgios has defeated Nadal three times before, their rivalry one of the most entertaining contests in world tennis.
Former world number one Courier claimed Kyrgios is "not afraid" of the looming threat of facing the Spaniard in the fourth round.
"(Nadal) looked great, but keep in mind that Nick has won quite a few of their contests, including Wimbledon a few years ago," Courier said on Channel Nine's coverage of the Australian Open.
"So he's not afraid of Rafa and that's a match where, for Nick, he's not expected to win. He can perform at his best and if it's not enough, well no worries, you lost to the No. 1 player in the world."
Kyrgios has been a leader in supporting the Australian bushfire appeal among sporting personalities, something Courier believes that extra motivations energised him.
"I think he's really thriving. In the past, he's put a lot of his focus and energy on his (charitable) foundation and playing for that and this year, the bush fires have been an emotional grab-point for him," Courier said.
"It's really given him something more to play for than himself. He thrives in team events, he loves to be a part of a team. He's really part of this big bush fire support team now, he's been a leader in it, and I think that's really depressurising him on court and energising him at the same time."
German star's incredible donation pledge
World No. 7 Alexander Zverev has promised to donate his entire Australian Open prize money to the Australian bushfire appeal if he wins the tournament.
After his first round victory over Marco Cecchinato on Tuesday evening, Zverev promised to donate "every cent" if he won his maiden Australian Open singles title.
"I will donate $10,000 for every match I win here," Zverev said after the match.
"I know I'm not the favourite, but if I win this event I will donate every cent to the bushfires.
"Australia is a country that is home for us for over a month every year. We heard what is going on with the bushfires, with the animals and with people losing their homes. So thank you very much, I hope we get a lot of support."
The winner of the Australian Open receives AU$4.12m.
Zverev will face Egor Gerasimov in the second round on Thursday.