Australia 'putting as much pressure as possible' on Joe Root, says Australian head coach

England find themselves 2-0 down in the Ashes so far, and Australia's head coach has pointed towards the work his side have done to keep opposition captain Joe Root quiet.

It's clearly a plan that is working - in the first two Tests Down Under, Root has two unconverted fifties, and is still yet to hit his first hundred on Australian soil.

That's despite the 30-year-old enjoying a career-best year with the bat, where he's reeled off 1,630 runs at an average of 62.69 including six centuries.

He's no doubt England's biggest threat, and Justin Langer admitted that his side was well aware of Root's ability.

"He is a brilliant player, no doubt about that, and we spend a lot of our time working out how to get on top of Joe," he said.

"That's not only because he's such a world-class player, but he's also the captain of the opposition. It's always been a philosophy in the Australian cricket team to put as much pressure on the opposition captain as possible.

"Joe Root is tough though, we say he hasn't necessarily got a really big 100 yet, but he's been an excellent player in this series already so we'll continue to do our homework on him and make sure, or hope, that we can keep having good effects with him."

Australian pressure isn't the only thing Root is having to deal with either. In the second Test, England's captain was twice struck in his groin area, leaving him in agony as he was dismissed for just 24 in the second innings.

He'll be hoping for a better showing in the third Test in Melbourne, which starts late on December 25 and runs through to Dec 30.

As for Australia's lineup, Langer commented on the poor form of Marcus Harris, who has managed just 38 runs in the four innings so far.

But despite facing competition from the experienced Usman Khawaja, Langer confirmed that he's opted to stick with Harris for the third Test, and that he already knows he'll start in Melbourne.

"He'll play in the Test, no worries about that," said Langer.

"This is his home ground. He's played a lot at the MCG. He hasn't made the runs he'd like to so far, but he dominates domestic cricket.

"We like to back our players where we can. He showed glimpses in Test cricket so far, and we're hopeful that he'll keep kicking on and keep getting better. It's a tough, tough gig Test cricket.

"But we're really confident. Marcus has got what it takes to to be a successful Australian opening batsman. What we see in the nets, what we see in domestic cricket all adds up to watch what is potentially a very good Test career. So let's hope he starts that off again on Boxing Day."

The Aussies are also leaving it late to assess the injured duo of Mitchell Starc and Josh Hazlewood, while captain Pat Cummins will return from his period in isolation.