Australia's Nick Kyrgios also cantered into the second round, but fourth seed Daniil Medvedev had to fight his way past American Frances Tiafoe in four sets.
World No.1 Rafael Nadal has praised the "very brave" ball girl who bore the brunt of his legendary forehand in "one of the more scary moments" of his glittering career on Thursday night.
Nadal on Thursday muscled his way into the third round with a commanding 6-3, 7-6 (4), 6-1 victory over Argentine Federico Delbonis. Serena Williams won the Auckland Open at the start of the month and she seems to be playing with great intensity and confidence.
Italy's Fabio Fognini, two sets down against America's Reilly Opelka when their match was suspended on Monday, returned to win it in five on Tuesday after a stormy encounter when both players argued furiously with the umpire. Experts estimate that more than one billion animals have been killed during the crisis, which has destroyed around 16 million acres of land.
Only one adrift of Roger Federer's record haul of 20 grand slams, Nadal has reached four finals at Melbourne Park without success since claiming his sole Norman Brookes Challenge Cup 11 years ago.
Krajinovic's first-round match was delayed because of heavy rain on Day 1 of the tournament, and he had to get through a tough five-setter against Quentin Halys.
Nadal, in a pink sleeveless shirt and matching shoes, was in total charge against the world No. 73 Dellien, storming to a 5-0 lead in the opening set before the Bolivian held serve then, against the odds, broke, before the Spaniard served out the set.
Uber sells Indian Eats business to Zomato in move to cut losses
The Zomato and Uber Eats combine will change the dynamics even further by giving Zomato's user base a big boost. Facing stiff competition from Zomato and Swiggy, Uber Eats had been making losses.
"I knew I had to play better - I couldn't keep making unforced errors like that and I knew that I had to step up or it was going to be a really long evening for me".
Wawrinka, the 2014 champion, was pushed hard by Andreas Seppi, but the Swiss made it 10 wins in 14 meetings with the Italian veteran, securing a 4-6 7-5 6-3 3-6 6-4 victory.
"You have to accept them and embrace the fact that, I guess, you're going to be challenged on different levels, not just by your opponent, but also the conditions". I feel the support.
"I always dance. I'm not the best dancer, but I love dance", Williams told reporters.
Now world no. 1 the Spaniard reached the 2 round after defeating Hugo Dellien 6-2 6-3 6-0.
Millman had previously asked to be scheduled to play on Melbourne Arena because it is a rowdier stadium where spectators can enter the venue with a standard ground-pass ticket.
The pick for Tennis Tonic is Alexander Zverev that should win in 3 sets.