Mulder's mammoth effort went past the 311 not out that Hashim Amla scored against England at the Oval in 2012, the Proteas' only other individual triple centurion in the longest format.

Mulder's innings was the sixth highest individual score in Test history while the all-rounder became the 29th Test cricketer to strike a triple hundred.

It was also the second fastest 300 recorded in Test cricket, coming off 297 deliveries - beaten only by India's Virendar Sehwag's 278-ball effort against the Proteas in Chennai in 2008.

In what is his first match as captain of the Proteas, Mulder also beat Graeme Smith's mark of 277 as the highest score by a South African skipper in a Test match.

With Brian Lara's world record of 400 in his sights, Mulder decided to declare his team's innings at lunch on the second day at the Queen's Sports Club.

In a post-play television interview, Mulder said: "First things first, I thought we have enough runs we need to bowl. Secondly, Brian Lara is a legend let's be real, he got 400 against England and for someone of that stature to keep that record is pretty special.

"I think if I get the chance again, I'll probably do the same."

The Proteas' bowlers then set to work after the lunch interval and dismantled the home side's batting order, Zimbabwe 170 all out and being forced to follow-on.

Mulder was also in the wickets as he picked up 2-20 in six overs but it was off-spinner Prenelan Subrayen, on Test debut, who was the pick of the Proteas attack with figures of 4-42 in 10 overs.

Zimbabwe fared much better in their follow-on innings, reaching 51-1 at the close of play with opener Takudzwanashe Kaitano unbeaten on 34 and Nick Welch on 6 not out.

Proteas coach Shukri Conrad said of Mulder's monumental knock: "Wiaan's innings was nothing short of extraordinary.

"Being the captain, then batting at number three where he had to absorb early pressure and face the new ball, which he did with immense composure and control - it was unbelievable.

"The way he constructed his innings, session by session, was a masterclass in temperament and shot selection.

"It's the kind of performance that anchors a team and sets the tone for the entire match. We're incredibly proud of what he's achieved today."

The Proteas currently hold a 1-0 lead in the two-match series against Zimbabwe, with their victory in the first game bringing them level with the all-time national record of nine consecutive Test wins, a milestone set between March 2002 and May 2003.

A victory in the current Test would see them surpass that record and reinforce a dominant run of form in the longest format.

Highest individual scores in Test cricket

400* - Brian Lara for West Indies v England, Antigua 2004

380 - Matthew Hayden for Australia v Zimbabwe, Perth 2003

375 - Brian Lara for West Indies v England, Antigua 1994

374 - Mahela Jayawardene for Sri Lanka v South Africa, Colombo 2006

367* - Wiaan Mulder for South Africa v Zimbabwe, Bulawayo 2025

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