Coric in racquet-smashing tantrum in loss to Millman

Volatile Croatian Borna Coric has capped a day of meltdowns and blow-ups with a huge tantrum against Aussie John Millman.

Millman upset the odds to give local fans another player to cheer for in the second round of the Australian Open.

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Millman, the world No.122, defeated Coric 7-5 6-4 6-1 in two hours and 19 minutes on Monday - joining compatriots Nick Kyrgios, Matthew Ebden and Olivia Rogowska as day-one winners.

Coric, 21, is seen as a dominant player of the future, having finished in the year-end top 50 for three straight seasons.

But the 28-year-old Queenslander showed him up on show court three, racing through the final set in half an hour to return to the second round as he did in 2016.

And as the match was slipping away from Coric, the young gun had a bit of a meltdown.

After engaging in a running battle with the chair umpire all match, Coric destroyed his racquet after losing a point.

The Croatin slammed it into the court three times, before tossing it over towards his chair and kicking it for good measure.

It certainly was an eventful opening day at Melbourne Park, with Coco Vandeweghe also blowing up - over bananas of all things.

Vandeweghe refused to take the court to start the second set because she hadn't been given a banana, and was also docked a point for unsportsmanlike conduct when she swore at her opponent late in the match.

Russian 31st seed Ekaterina Makarova also destroyed a racquet after her shock first round loss.

And German showman Dustin Brown channelled the 'super brat' John McEnroe when he told an umpire "You cannot be serious" after disagreeing with a line call.