As McSweeney walked out to the middle of the WACA amid a warm sunny morning, with quicks Pat Cummins and Mitchell Starc raring to go, some of his new team-mates decided to rib him.

"Welcome to Test cricket," they chirped.

McSweeney, 25, was put through a thorough examination on the centre wicket as he took turns with Khawaja and Steven Smith in facing Cummins and Starc with the new ball.

It was a baptism of fire and McSweeney looked rather uncomfortable as he played and missed repeatedly. But batting was made more difficult on the western side of the square which sloped away from the right-hander.

Smith lamented the conditions, while McSweeney had a torrid time particularly against Cummins who consistently angled in and seamed away down the slope. He struggled to lay bat on ball, but there were some encouraging signs.

"It was a good challenge. I got through it unscathed," McSweeney told reporters on Monday. "Didn't put much pressure on them but they bowled really well and great preparation to face those guys who are quality bowlers."

McSweeney had a better time against offspinner Nathan Lyon, who he played comfortably, before undergoing more batting practice at the WACA nets. He finished his maiden session by bowling to Starc and Cummins. His handy offspin likely to be needed at some point during the Test series.

"I think nothing but exceptional in my eyes," Lyon said of McSweeney's character. "I saw him up close and personal in that Shield game a couple of weeks ago [South Australia vs New South Wales] and I thought we had to run him out to get him out in the game.

"I thought his tempo was nice. His timing of his movements were in sync. I've got nothing but praise for Nathan the way he's gone about it. He's a great guy, great kid and I only wish him the best."

McSweeney will also play a role in shoring up Australia's slip cordon after the retirement of David Warner, while Cameron Green's absence also leaves a sizeable hole at gully.

On Monday, McSweeney was stationed at third slip for catching practice with Smith on his left at second, Khawaja at first and Marnus Labuschagne in the gully. He also moved to a second gully for a few catches, standing on Labuschagne's right in an indication that he might be used as a floater and rotate between third and the extra gully depending on where he's needed.

"Early days of my Shield career was at third and a little bit at gully," McSweeney said. "Undecided exactly where I'm going to field but comfortable in both. It's pretty cool standing in the slip cordon next to Steve Smith."

But as he starts to experience the scrutiny that comes with being a Test cricketer, his selection did receive some backlash with former Test opener Ed Cowan particularly vocal.

"I think everyone is going to have their opinion. I try and not read too much into it," McSweeney said. "I have the guys in my corner. I really trust and value their opinion and I haven't spent heaps of time with Ed.

"I think for me I know what works and I feel very capable to go and do the job and I'm batting the best I ever have, I feel. Hopefully I can go out there and execute that on Friday."

Adding to his set of challenges, McSweeney has never played red-ball cricket at the 60,000-seat Optus Stadium. Isaac McDonald, the ground's curator, is hoping to replicate the spicy conditions of last year's Test between Australia and Pakistan where numerous batters copped blows to their bodies.

The advice from his senior team-mates? "Try and make sure you spend some time in the nets and get used to the bounce," McSweeney said. "That's one thing that's spoken about a little bit.

"The other thing is own your space in terms of what I've done for South Australia. Execute the same thing and the same process, same routine.

"Ultimately it's the game of cricket and I know my game."

While he learns to cope with the whirlwind of being a Test cricketer, McSweeney will lean on the support from loved ones descending to Perth in large numbers.

"A lot of friends will be there, and mum, dad, my sister, grandad, my partner and a lot of guys I played club cricket with back in Brisbane," McSweeney said.

"Got a great supporter base and great family that's looked after me and sacrificed a lot. Just looking forward to taking it all in and being able to share the moment with them."