Aussie-born Brit Johanna Konta has sent Venus Williams crashing out of the Australian Open at Melbourne Park.

In a centre-court boilover, Konta backed up her breakout 2015 season with a crushing 6-4 6-2 first-round victory over the seven-times grand slam champion on Tuesday.

Konta struggled to digest one of the biggest wins of her career.

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“When the draw came out and I saw who was playing, I just hoped to stay out there more than an hour,” she said.

“I played two previous tournaments (this year) and I didn’t have the results I wanted but I have a very strong belief.”

While Williams perished, Spanish third seed Garbine Muguruza had no such troubles earlier in advancing to the second round with a 6-0 6-4 win over Anett Kontaveit of Estonia.

In her first match since withdrawing from the Brisbane International with a foot injury, Muguruza outclassed Estonian Anett Kontaveit 6-0 6-4 in precisely an hour on Rod Laver Arena.

“I had a few problems in my foot but I think I am recovered now,” the 2015 Wimbledon finalist said after breaking her opponent four times and being completely untroubled on her own serve.

Swiss 11th seed Timea Bacsinszky is also through after beating Czech Katerina Siniakova 6-3 7-5, while American 15th seed Madison Keys ousted Zarina Diyas of Kazakhstan 7-6 (7-5) 6-1.

Two Australian wildcards have been eliminated on Tuesday.

Ekaterina Makarova, the 21st seed, dispatched Maddison Inglis 6-3 6-0 and German Annika Beck beat Priscilla Hon 6-0 6-3.

On the men’s side, Bernard Tomic dropped the opening set but not his bundle in downing Denis Istomin to reach the second round.

Tomic was often put under the pump by Istomin but rallied when required to prevail 6-7 (4-7) 6-4 6-4 6-4 over Istomin in three hours on Tuesday night.

The match was interrupted for more than 20 minutes early in the fourth set because of a spectator’s medical condition.

Sam Groth claimed his first victory since last year’s US Open by powering past Frenchman Adrian Mannarino.

The reigning Newcombe Medallist quickly overcame a third-set blip against Mannarino to win 7-6 (8-6) 6-4 3-6 6-3, setting up a second-round clash against No.2 seed Andy Murray.

It was a drought-breaking victory for Groth, who had lost in the first round of his past four tournaments, including the Brisbane and Sydney Internationals.

Fellow Aussie John Millman earned a passage to the second round when opponent Diego Schwartzman retired with the score at 3-6 5-7 7-6 (7-2) 5-0.

Schwartzman was badly restricted by severe cramps on a hot day in Melbourne, and needed to be stretchered from the court by medical staff after the match.

Earlier on Tuesday, Australian teenagers Maddison Inglis and Priscilla Hon were beaten in straight sets on their grand slam singles debuts.

Inglis, 18, went down 6-3 6-0 to No.21 seed Ekaterina Makarova from Russia, a semi-finalist at Melbourne Park last year.

-AAP