The crowd by Court 7 seemed well behaved, at first.
They waited for a break in play before filling and vacating seats. They offered appropriately timed oohs, ahhs and cheers for the two Aussie wildcards, Alex Bolt and Andrew Whittington, and parochial silence or grudging applause for their doubles opponents, Mahesh Bhupathi and Gilles Muller.
It didn't take long, however, for the sleeveless T-shirt crowd, flag bearers and wearers, the kangaroo clique - the boys with the beer - to offer a disparaging remark or two. For their impatience and the sun to breed a little disrespect for proceedings. 
In a tense final game of the second set, for instance, one fan offered some choice advice. His booming directive was aimed at the locals, who were dressed in blue, the same colour as the courts: "Utilise your camouflage, boys. Come on! Get on it!"
As far as bad barrackers go, it could have been worse. It has been already, in fact. On day one of the Australian Open, in a match between Melbourne boy Omar Jasika (ranked 310) and Illya   Marchenko (ranked 76) of Ukraine, the noise and (at times) abuse clearly upset the foreign player. That same day, crowds began to niggle Nick Kyrgios in his first-round clash. He reportedly complained to those near him after several points, finally pleading: "It's not Toyworld out here".
On day two it continued, a few wannabe fanatics ruling the stands in a hard, tense match between Australian right-hander Matthew Ebden and the favoured Marcel Granollers.
The Spaniard eventually won, but not without struggle - or anger. At one point he argued with an umpire and offered up his frustration by simply sitting down. And didn't the crowd fairly pounce on his mild protest. Having once chanted "Aussie Aussie Aussie" they now went a different way. Led by a man in green and gold gear, and a slouch hat with corks dangling from strings, they niggled and mocked.
"If you're happy and you know it clap your hands!" he sung.
"Take it to him, Matty!" boomed someone else. "Time violation!" laughed another.
But how bad is it? When does nationalistic banter become malicious - and are Aussie crowds any worse than those abroad?
Barry Flatman, tennis correspondent for the Sunday Times in London, has seen the game played all over the world and concedes there is "something" about Australian Open crowds. "By and large, they're good and enthusiastic and not in any way nasty, but they're a little rowdier - certainly than Wimbledon and probably the French Open," he said. "I probably sound like a typical British guy, but it's not the same reverence that's shown at Wimbledon."
It could be a function of ticket price. Matches, particularly in week one of the tournament, are far more accessible here than in other majors.
"Melbourne's probably the greatest city for watching sport in the world," said Flatman, "but they might not be well versed in tennis, and that can create the odd problem."
He has seen the same effect at Flushing Meadows, where American crowds stand out as far worse. Take for instance the boorish barracking against Novak Djokovic in the US Open final against Roger Federer.
The support was far from harmless partisan barracking for a crowd favourite. Fans openly tried to distract The Djoker as he was preparing to serve - and cheered when he faulted.
THE BEST OF TODAY'S OPEN ACTION
AUSSIES
Rod Laver Arena
Not before 2pm
Sam Groth (Aus) v 2-Andy Murray (GB)
From 7pm
8-David Ferrer (Spa) v Lleyton Hewitt (Aus)
Margaret Court Arena
After 7pm
(second match) Bernard Tomic (Aus) v Simone Bolelli (Ita)
THE BIG NAMES
Rod Laver Arena
From 11am
Anastasija Sevastova (Lat) v 20-Ana Ivanovic (Srb)
Kirsten Flipkens (Bel) v 3-Garbine Muguruza (Spa)
Margaret Court Arena
From 11am
23-Gael Monfils (Fra) v Nicolas Mahut (Fra)
CARNAGE IN THE WOMEN'S DRAW
WOMEN'S SEEDS OUSTED
Seeded first round losers
Simona Halep (2)
Venus Williams (8)
Caroline Wozniacki (16)
Sara Errani (17)
Andrea Petkovic (22)
Sloane Stephens (24)
Samantha Stosur (25)
Anastasia Pavlyuchenkova (26)
Anna Karolina Schmiedlova (27)
Irina-Camelia Begu (29)
Lesia Tsurenko (31)
Caroline Garcia (32)
THE BAD SEEDS
Women seeds to lose in the first round of a grand slam event since the 32-seed system was introduced in 2001
Australian Open 2016 12
Australian Open 2015 11
Wimbledon 2004 11
French Open 2002 11
US Open 2012 10
US Open 2015 10
AVERAGES
Australian Open 6.5
Wimbledon 6.4
US Open 5.7
French Open 5.7