Bongi Mbonambi was struggling, says Rassie Erasmus after substitution

Bongi Mbonambi was replaced by Malcolm Marx before halftime in the Springboks' match against the Wallabies. Laurence Griffiths, Getty Images

Springbok coach Rassie Erasmus says hooker Bongi Mbonambi was substituted in the first half of their Rugby Championship match against Wallabies because he was 'struggling'.

Mbonambi was replaced by Malcolm Marx shortly after a botched lineout close to the Springboks' tryline lead to a try for the home side, who eventually went on to win the clash 23-18.

Erasmus denied that Mbonambi was taken off the field because of the try, and said he was replaced because he was battling to keep up with the match.

"Bongi has not played a lot and you could see he was struggling," Erasmus said after the match.

"You can ask the guys, the deal is everyone plays as long as he can and as soon as you start struggling, the sub comes on. I substituted my captain [Siya Kolisi] a few times during the June Tests.

"We tell the guys to empty the tank, see how far you can go and then we will bring the guy on the bench on and he will try to finish the match. It definitely was not for the overthrow because that was more a combination between Siya and the guys. It definitely wasn't his fault."

Individual mistakes derailed the Springboks' ambition of gaining a valuable away win in Brisbane, as the Wallabies defeated the visitors in an error-strewn match. The home side were trailing 18-17 at the halftime break in this round three match of the Rugby Championship.

Erasmus, who also SA Rugby's Director of Rugby, afterwards bemoaned the many individual mistakes made by the Springboks.

"To gift 14 points on a platter to a team, you're (always) going to struggle to win the game," said Erasmus after the Wallabies took advantage of early Springbok mistakes to score two first half tries.

"I thought our mauling went very well compared to last weekend, the scrums were good in the first half, but then there were moments when we lost vital scrums and lineouts, so it was a mixed bag of different mistakes," was Erasmus' assessment of the match.

The stop-start nature of the match meant the Springboks were unable to build any real sustained period of dominance, although this time around, the South Africans made a more positive start to the game than in previous matches so far this year.

"We were awful in the second half and played better in the opening half," stated the Springbok mentor.

The Springboks now travel to New Zealand on Sunday where they will take on the All Blacks in Wellington next Saturday in the second away match of their Australasian tour.

Erasmus admitted that facing the New Zealanders in their own backyard will be a daunting task: "We are playing the best team in the world, we've just lost two matches in a row so the pressure is on us."