CAPE TOWN, Oct 27 - Fast bowler Mitchell Starc did not know Australia’s premier batsman Steve Smith would not take part in the decisive third test against South Africa at Newlands on Tuesday until he went to warm-up ahead of play.

Smith tested his neck injury in the nets on Tuesday morning but was still experiencing discomfort, captain Pat Cummins said at the toss.

"He wasn't happy with how his neck was feeling, so we had to look elsewhere," Cummins said.

Smith's absence meant he would not feature at the ground where he was embroiled in the 2018 ball-tampering 'Sandpapergate' scandal, with much of the pre-match focus centred on how Australia's most experienced batsman would cope with the occasion.

"I did not know he was not playing until I went out to warm-up today," Starc told reporters after the day’s play. “He has been battling that neck since last week.

“I don’t actually know what happened with that and I have not asked. He seems upbeat enough, but I don’t know what he has had done.”

After winning the toss, Cummins opted to bowl, a rare decision at Newlands that might have been taken with the reshuffle of the top six batsmen after Josh Inglis learnt just before the start he would replace Smith.

The move initially appeared to have backfired as South Africa made a strong start. However, Starc produced a masterful spell with the second new ball late in the day, finishing with figures of 6-72 as the hosts were dismissed for 329 on the stroke of stumps.

“I am not in that pay bracket,” Starc said when asked if he agreed with the decision to bowl first. “My opinion doesn’t matter. It is what it is. At one point it looked like we were bowling a fair bit tomorrow, so it was good to bowl them out today.

“There was clearly not as much swing and sideways movement as we thought might be on offer (early in the day). But we found different ways to be effective and if you delete that first session, I think the last two were back on what we expected.”

It was another see-saw day in a series that has already seen plenty of twists and turns.

“These are two very good cricket teams. At times it is going to get away from you, at times you will wrestle the momentum back, which we did in the second half the day,” Starc said.

“I expect more swings through the test match as we now need to go and bat and they have a very good (bowling) attack.” REUTERS