Pat Cummins has escaped a heavy collision without injury — but with a wicket — on Australia’s march towards a 74-run first-innings lead over South Africa in the World Test Championship final.

Starting day two in serious trouble at 4-43, the Proteas were able to frustrate Australia’s star-studded bowling attack and move to 5-121 at lunch on day two.

But Cummins struck twice in one chaotic over early in the second session and then cleaned up the tail to finish with 6-28, with South Africa all out for 138.

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The Australian skipper trapped Kyle Verreynne on his pads and shouted his appeal while running backwards down the pitch, completely unaware that he was about to collide with his potential victim.

The umpire was halfway through rejecting the appeal when he, the crowd and commentators reacted with shock at the off-camera collision.

“He was absolutely T-boned there,” Matthew Hayden said of Cummins.

Cummins quickly got back to his feet and called for a review, with three red lights flipping the delivery from a dead ball to a wicket.

The captain pumped his fists in delight and did so again just three balls later when he had Marco Jansen caught-and-bowled for a duck.

Cummins’ last wicket of the innings was his 300th in Test cricket, and he had Beau Webster to thank for it after the allrounder took a brilliant catch just millimetres above the turf.

“It’s great, I’ve got some family here as well,” Cummins said of the milestone.

“It’s way more than I could’ve asked for so really happy. For any fast bowler 300’s a big number — it means you’ve battled a few injuries and niggles and got through it and played well in different conditions.”

The first fast-bowler to captain Australia long-term, Cummins joins the country’s greats in the 300 club.

Shane Warne (708 wickets) and Glenn McGrath (563) sit No.1 and No.2, while Nathan Lyon (553) and Mitchell Starc (384) are next in line.

Dennis Lillee (355), Mitchell Johnson (313) and Brett Lee (310) are the others to take more than 300.

Out of those eight players, only McGrath has a better average (21.64) than Cummins (22.08).

Cummins’ 6-28 against South Africa was his fifth six-wicket haul and just shy of his career best 6-23 against Sri Lanka at the Gabba in 2019.

But it demolished the previous best figures for a captain at Lord’s, surpassing England skipper Bob Willis’s 6-101 against India in 1992.

Earlier, South Africa batted sensibly in the sunshine and attempted to keep the scoreboard moving in their chase of Australia’s 212 after being sent in to bat.

South Africa captain Temba Bavuma survived a controversial DRS decision, allowing him to make important inroads into Australia’s lead.

Adjudged lbw on 16 off Josh Hazlewood, Bavuma left it late to review, but eventually took the decision upstairs with four seconds remaining.

The ball would have been smashing into the stumps, but a spike on snicko incredibly meant Bavuma had survived.

Former England captain Alastair Cook said during radio commentary he didn’t believe Bavuma had hit it.

But after looking promising, highlighted by smashing opposing captain Pat Cummins for six, Bavuma (36) scooped a drive to cover where Marnus Labuschagne pulled off a terrific diving catch.

Cummins got the crucial breakthrough, gaining revenge for being the first bowler in the match to be hit over the rope.

South Africa, who won seven straight Tests to qualify for the final, are attempting to break a title drought in ICC tournaments dating back to 1998.

- with AAP