Sloppy again from Marchenko. Murray keeps asking questions of his opponent but it goes down as two unforced errors from the Ukrainian and Murray takes a commanding lead in this game.

That's the break for Murray. Marchenko looked like he had sorted his serve but Murray gets a smart return in and then the Ukrainian is unable to keep his volley in the court.

A big break for the world number one in this third set. Marchenko looks like he might be starting to tire.

While Murray battles hard over on Laver, another Brit is about to kick off his Australian Open at the far end of Melbourne Park.

Dan Evans, Britain's number three, is out onto court 14, with Argentine leftie Facundo Bagnis standing at the other side of the net.

And Evo comes into the year's first major on the back of a cracking start to 2017.

The 26-year-old Brummie reached his first ATP Tour final in Sydney last week, although lost 7-6 (7-5) 6-2 against veteran Gilles Muller.

How deep can he go here? He has never moved past the first round in Melbourne...

Image source, EPA

Image source, Getty Images

Barely breaking sweat, done and dusted inside a couple of hours, a straight-sets win. That's ideally what the top seeds want in the first round of a Slam.

Not what Marin Cilic has got. The Croatian seventh seed, fresh from the best year of his career, makes hard work of Poland's Jerzy Janowicz.

Janowicz, ranked down in 278th, stormed into a two-set lead and must have been thinking he was about to win at a Slam for the first time in five attempts.

Cilic had other ideas. He sticks his name in round two after a three-hour marathon. 

It looked there for the taking for Murray. Marchenko can't get his first serve in and then clips the net on the second, but Murray can't take advantage.

He has another break point though, as Marchenko double faults again.

Double fault from the Ukrainian. That gives Murray a chance to break here. Pressure on the world number 95.

Now it's Marchenko who is giving himself a talking to under his breath, he's not happy at giving that first service point away.

The Ukrainian fires a powerful forehand down the line to get Murray scrambling on the next shot, and a high, lofted return from the Scot is smashed across court by Marchenko.

That's better from Murray, no messing with some quickfire points that leave Marchenko no chance and he takes his service game.

That's high, wide and not at all handsome from Murray as he flicks a backhand out of play. Marchenko then follows suit with his own mishit from a Murray serve, a nice chunk of frame on that one and it goes long.

Image source, AP

Another neat volley at the net from the big Ukrainian, he flies in there to dispatch Murray and then is clinical on the next service point to take the first game.

We're back after a quick change of clothes, I think, for Marchenko. The world number 95 looks pretty tired and he was drenched after those first two sets.

But he's taken an early lead in this game, going 30-15 up with a subtle drop shot.

That's the set for Murray, he moves into a 2-0 lead with a powerful forehand that Marchenko can only send long in return. A big first pump from the Scot, who was forced to work for that one - 76 minutes for the set.

Both players look exhausted, but Marchenko nabs another point, before a Murray error from his forehand brings the score to 6-5.

So Murray has the chance to serve this tie-break out, he puts his first serve into the net and then somehow digs out a backhand response when Marchenko's return looked to have beaten him, but the world number one goes long with his next shot.

He's more clinical with the next serve, Marchenko can't make any meaningful return and it's 6-3 and set point.

Plenty of grunting from both men, but Marchenko steals back a point with a powerful swat that Murray stands and watches sail past him. 4-2.

Murray lets out a yell of annoyance and then fist pumps as Marchenko's forehand falls wide again. 5-2 to the Brit.

Murray's back on serve, and it's a powerful one from the world number one as Marchenko can only respond by sending the ball low into the net.

The Ukrainian is able to engage him in a rally on the next point, several looping forehands are exchanged before the world number 95 drags his attempt well wide. 4-1 Murray.

Long old rally, but it's Murray who comes out on top as Marchenko rushes his forehand and slices the ball out. 2-1 Murray.

First blood Marchenko, he forces Murray wide and takes the point, but follows up with a wayward backhand to make it 1-1.

A slice of luck, a wonderful shot...and then Marchenko takes Murray to a tie-break with another big winner. Pressure on for both players here.

Image source, AFP