Michael Clarke is fit and Mitchell Johnson feels ready to fire, but day one of the first Test against India holds a sense of the unknown for Australia.

Clarke has recovered from a recurring left hamstrung injury and will captain the side on Tuesday, with Peter Siddle edging Josh Hazlewood to claim the final pace berth in the XI.

It will be a highly-emotional affair, with Australia playing their first game since Phillip Hughes died after being felled by a bouncer.

Hughes has been named 13th man and will be the subject of a range of tributes at Adelaide Oval.

Apprehension clouded Australia’s training session on Friday, as they wrapped their minds around hooking short balls and sending down bumpers two days after Hughes’ funeral.

Confidence returned over the weekend, but mourning in the middle of Adelaide Oval will be a long way removed from the nets.

“The first spell might be the most difficult,” Johnson said, conducting the captain’s pre-match press conference in place of grief-stricken Clarke.

“Then we might just get back into the game a bit more.

“We’ll have to wait and see when we get out there … we’re all probably going to feel a little bit different.

“The vibe is good. Everyone’s really keen to get out there and play some cricket.”

Johnson’s intimidatory pace and bounce powered Australia’s 5-0 Ashes thumping of England last year, with Kevin Pietersen saying he was “petrified”.

The 33-year-old has struck plenty of batsmen in his career, earlier this year knocking out South Africa’s Ryan McLaren.

“I haven’t hit anyone yet so I don’t know how I’m going to feel,” Johnson said.

“It might be different (reaction) this time.”

There’s a chance it will happen, with the fiery left-armer promising the hosts won’t hold back with the ball in hand.

“We’ve got to play the way that we’ve been playing and that’s been aggressive,” he said.

“If that is bowling the short ball like we have been, then that is what we will do.

“The last 18 months I’ve been very aggressive and I’m not going to change that.”

Johnson admitted he found it “very difficult” batting and bowling in the nets on Friday.

The reigning ICC cricketer of the year didn’t feel comfortable bowling a bouncer until late in the session.

“The more I’ve bowled, the better I’ve felt,” he said.

“I’m glad we’ve been able to get out there and be able to bowl short ones and get in the nets and face a few.

“The level of intensity was probably up there with the best that we’ve trained in a long while.”

Johnson met with Corporal Ben Roberts-Smith, a recipient of the Victoria Cross, in 2012 when his career was at the crossroads.

The wisdom Roberts-Smith passed on will be on Johnson’s mind at the top of his mark on Tuesday.

“You can’t let emotions get in the way. You have to go out and play your skills and be switched on,” he said.

“I know our guys will be.”