GQEBERHA, South Africa, Oct 20 - A test career of cameo appearances and fleeting glories has been Scott Boland's lot since his explosive Ashes debut five years ago but the pace warrior has rarely let Australia down when given half a chance.

In Gqeberha, Boland has delivered again in his first test since January to give Australia the upper hand as they look to seal their three-match series against South Africa with a game to spare.

The burly Victorian finished Monday's rain-hit day two with figures of 4-31 at St George's Park, leaving the hosts in trouble at 97 for 5.

It takes a special bowler to deny world-class spinner Nathan Lyon a place in Australia's attack, no matter the surface or conditions.

It takes an extraordinary one to operate at the highest level at the age of 37 and to hit the mark with such efficiency after a long period on the fringes.

Boland knew of his selection in Australia's starting side only minutes before the toss but wasted no time finding his line and length.

"Sometimes I'll take 30 balls just jumping through my action," he told reporters.

"I did it the other day and it took six. I was feeling good."

Boland struck in consecutive balls to remove Aiden Markram and David Bedingham on day one, then returned on day two to dismiss Marques Ackerman with his seventh ball of the afternoon.

Matt Renshaw took a screamer of a slips catch to help Boland capture his fourth wicket with an edge off Ryan Rickelton's bat.

Boland's haul so far in his 20th test has lowered his career bowling average to a tick over 18 -- the best of any bowler with 50 wickets since World War Two.

He is Australia's oldest specialist test quick since Ray Lindwall in 1960.

Heaven knows what Boland might have achieved with more opportunity in a lesser Australian attack -- or had he been plucked from Sheffield Shield obscurity well before his fairytale 2021 debut against England, when he took 6-7 at the Melbourne Cricket Ground.

Boland said he was in no mood to slow down and would gladly play every test if selected.

"I know I'm 37 and the oldest fast bowler to play for a while," he said.

"But still feel like I'm going really well and my body's in good spot. I feel like I can do it for as long as I can." REUTERS