World No. 2 Murray destroys local hope Groth on Day 4 of Australian Open

World No. 2 Andy Murray quickly hushed parochial Australian fans baying for a major upset on Day 4 of the Australian Open, demolishing starstruck local hope Sam Groth in straight sets.

In his first appearance on Rod Laver Arena (RLA) on Thursday, the late-blooming Australian - best known for producing the fastest serve ever recorded in tennis history - was given an unceremonious welcome by the Brit.

The two-time Grand Slam champion Murray, who went Slam-less last year, didn't give Groth an inch - or a game in the first set, for that matter - winning 6-0, 6-4, 6-1 in an hour and 29 minutes.

Murray said he went looking for blood after Groth, 28, inadvertently let him in on just how unfamiliar the surrounds of centre court were to the big-serving local.

"I was standing right next to him in the locker room and he said to someone: 'This is my first time on Rod Laver (Arena), I've never even hit on it before'. So I was like 'OK great, that's good for me'," said a slightly bemused Murray postmatch.

"I remember when I played my first match on centre court ... and it's very different to the outside courts."

Groth's usually reliable serve betrayed him in the first set, with the number-two ranked Brit able to break the Australian seven times.

"He didn't start the match off serving so well, which helped me. And then when he picked his serve up in the second set it became much tougher," Murray, 28, said courtside.

Earlier, the Day 4 session began with a distinguishable lack of star power, with the draw deprived of Rafael Nadal, Simona Halep and Venus Williams following their surprise first-round departures.

Making the most of their absence, 2008 Australian Open runner-up Anna Ivanovic was thrust into the spotlight on RLA, and scored a 6-3, 6-3 win over Latvian Anastasija Sevastova. In a relatively uneventful match, all the drama unfolded off the court.

A medical emergency in the stands, involving a spectator who apparently slipped while descending the stadium's stairs, kept players patiently waiting courtside for 35 minutes for play to resume.

It's the second time in three days that a major medical disturbance has occurred in the crowd, after a woman suffered an apparent seizure during Australian Bernard Tomic's first-round match on Tuesday.

Following Ivanovic's comfortable win, 3rd-seed Garbine Muguruza snuck past Belgian Kirsten Flipkens in an error-riddled 6-4, 6-2 victory.

Across on Margaret Court Arena, Frenchmen Gael Monfils and Nicholas Mahut went toe-to-toe, with the explosive Monfils packing too much power for his fellow countryman to win 7-5, 6-4, 6-1.

Before play got underway, Australian tennis legend John Newcombe, winner of seven Grand Slam titles, turned heads when he selected 13th-seed Milos Raonic to win the men's title.

But the young Canadian swiftly validated Newcombe's selection, going about his business with minimum fuss and effort by posting a 7-6 (8-6), 7-6 (7-5), 7-5 win over Spanish stalwart Tommy Robredo.

Another lowly-seeded dark horse in the women's draw, Victoria Azarenka, also progressed without great fanfare, despite another impressive performance in the second round.

The duel Australian Open-winner backed up her first-round 'double-bagel' - 6-0, 6-0 - with a 6-1, 6-2 sweep of Danka Kovinic of Montenegro, meaning she has only dropped three games through her first two matches.

"I really don't count the games," Azarenka said.

"I just enjoy myself on the court and try to play every point like it's my last point."

The 16th-seeded Bulgarian will play Elina Svitolina for a place in the fourth round, where she will likely meet Muguruza in a great test of both players' title credentials.

In other results, big-serving American John Isner negotiated his way through two tiebreakers to beat Spaniard Marcel Granollers 6-3, 7-6 (8-6), 7-6 (7-2), while Madison Keys survived a scare against Yaroslava Shvedova winning in three sets.

Weatherwise, Day 4 took a queue from its predecessor, with misty rain delaying proceedings on all outside courts at Melbourne Park once again. Endit