Michael Clarke overcame a serious back injury to celebrate an emotional century as Australia moved to 6-433 on day two of the first Test against India.

Clarke (102) and Steve Smith (109) shared an 86-run unbeaten stand after 107 overs on Wednesday, when rain regularly delayed play at Adelaide Oval.

Clarke and Smith both paid tribute to friend Phillip Hughes when they reached triple figures.

The captain brought up his 28th Test ton in the second over after tea, with the final session due to end at 6.30pm local time.

Clarke retired hurt on 60 on Tuesday, when he was sent for scans and received injections following a flare-up of his chronic back injury.

But the skipper donned a back brace and strode onto Adelaide Oval on Wednesday, despite Australia’s team physiotherapist Alex Kountouris admitting the captain was “struggling”.

“Unfortunately it’s quite a significant back injury,” Kountouris said before play.

Clarke was clearly restricted – there was no trademark fancy footwork and he limited his shot selection to minimise twisting at the crease.

The 33-year-old grimaced regularly, but India failed to make the most of overcast conditions after Australia resumed day two at 6-354.

Clarke’s running between the wickets was understandably slow, but he and Smith kept the scoreboard ticking over in the morning session with a handful of sweetly-timed boundaries.

Clarke has three degenerative discs in his lower back and every shot caused a clear pang.

“He’s showing a lot of courage … he’s hurting,” Shane Warne said while calling the game for the Nine Network.

“Some (strokes) are going to hurt a lot more than others, but he’s in a lot of pain.”

The skipper overcame a recurring left hamstring injury to play the rescheduled first Test.

But Kountouris believed his current woes were unrelated to the hamstring issue.

“This is his right lower back. This is his old injury, what he’s had in the past,” he said.

“I don’t think it’s directly related to his hamstring, because it’s the other side.

“We believe it’s related to his old disc injuries. With that comes a lot of muscle spasms and other things that cause pain.”

Rain delayed the start of play by 10 minutes on Wednesday, while the umpires called for the covers at 11.26am local time before changing their mind.

Soon after they had no choice as heavy rain started to soak the pitch.

Umpires snuck in 11 balls after lunch before calling for the groundsmen again.