South Africa coach Jacques Nienaber believes recent World Cup glory could give his players the edge during Saturday's series decider against the British and Irish Lions.

The Springboks go into the winner-takes-all contest in the ascendency after leaving proceedings tantalisingly poised thanks to last weekend's resounding 27-9 success.

Lions boss Warren Gatland suggested the hosts spent considerable emotional energy in levelling the series and has responded to his own side’s shortcomings by making six changes for this weekend’s crunch clash in Cape Town.

Nienaber – who served as defence coach under Rassie Erasmus when the Springboks were crowed world champions in 2019 following victory over England – feels the rival teams are under similar pressures and thinks his squad will benefit from the experience of lifting silverware.

South Africa thumped the Lions 27-9 last Saturday to set up a series decider

"Big games like this takes a lot of energy out of you in the build-up, a lot of emotional energy. It’s draining because there is so much at stake," he said.

"I didn’t see Warren’s comment but yes I agree with him if he’s saying there’s a lot of emotion going into these games.

"It’s something that we will have to handle as a group and it’s the same with them.

"Luckily for us in our group, they’ve been there before. It doesn’t make it easier but it helps you having that experience.

"I’ve been there before I’ve felt these butterflies before and you just have to work through it.

"It’s a do-or-die for both teams, it’s a final and it’s going to be massive."

Nienaber has been forced into two personnel changes to his starting XV after influential duo Faf De Klerk and Pieter-Steph Du Toit were ruled out by injury.

Star scrum-half De Klerk has a leg muscle strain and been replaced by Cobus Reinach, while 2019 world player of the year Du Toit requires further assessment on a shoulder issue suffered on Saturday, meaning Franco Mostert switches to openside flanker and Lood De Jager is brought in at lock.

Reinach comes in from the cold for his first minutes of the series as the preferred half-back partner for his Montpellier team-mate Handre Pollard, leapfrogging replacement Herschel Jantjies into the No 9 jersey.

Nienaber has backed the 31-year-old to provide seamless cover for De Klerk.

"With the type of rugby we play and the game plan we play with, we feel Cobus and Faf, their style of play and the skill-sets that they bring to our team is similar," he said.

"With Herschel it’s a little bit different, out of the box.

"For us, going forward into this Test match, we feel it’s a like-for-like change in terms of bringing Cobus on and then we have Herschel that can always bring that (threat) offensively – like he always does – off the bench.

"That’s the (thinking behind) the decision to bring Cobus in from outside the 23 into the starting line-up."

Veteran out-half Morne Steyn could make his first Test appearance since October 2016 after being recalled to the bench but No 8 Duane Vermeulen (ankle) and prop Ox Nche (neck) will not be involved.