Schalk Burger said a mixture of wise old heads and youthful energy was the key for South Africa as they marched on towards the Rugby World Cup semi-finals.

The 32-year-old veteran flanker heaped praise on the Springboks’ old guard and their young guns after their thrilling 23-19 victory over Wales in Saturday’s quarter-final at Twickenham, which was secured with a try from captain Fourie du Preez five minutes from time.

“It could have gone either way, but the big thing was composure,” explained Burger, named man-of-the-match after a remarkable 26 ball-carries.

“The whole game from minute one was on a knife-edge,” said the 2007 World Cup-winner. “We obviously knew that this game was going to be won in the last 10 minutes.

“For the older guys, a lot of credit to them, they stayed calm. There were a lot of youngsters playing their first World Cup quarter-final. Hopefully, this will stand us in good stead for next week.

“We need energy but I think in big situations you also need a few old heads. We’ve pretty much seen it all in rugby, the senior players in this team.”

Burger said it was important to rest and regroup before next weekend’s semi-final.

“I’m going to drink as much beer as I possibly can. That was pretty intense. I need to relax now,” he said.

Apart from du Preez’s try, fly-half Handre Pollard, playing in his first World Cup, kicked the Springboks’ remaining 18 points.

The 21-year-old said scrum-half du Preez brought “calmness” to the South Africa side.

“He’s just an unbelievably calm character on and off the field. He’s so experienced, he makes the right decision 90 percent of the time,” said Pollard.

“He steers the ship in the right direction. It makes my job far easier.”

Pollard said playing at the England 2015 World Cup was a “gift”.

“It’s actually surreal. it’s like something you dream of,” the kicker said.

“Four years ago I was sitting in class and sneaking out to watch the World Cup. So it’s unbelievable to be here and just a great privilege.”

Pollard told AFP the Springboks had effectively been in all-or-nothing mode since their opening 34-32 defeat by outsiders Japan, the biggest Rugby World Cup shock of all time.

“For sure this team is growing from game to game,” he said.

“I feel us, a side, thrive under pressure. That brings the best out of us and makes us focus. We’ve been playing knockout rugby since we lost to Japan so we’ve been really focused and we’ve been in the same mindset for the last few weeks.

“But we didn’t come to the World Cup just to lose in the semi-finals, so we’re going to be up for it.”

Second row Pieter-Steph du Toit said the Springboks were turning the humiliation of losing to the Brave Blossoms to their own advantage.

“Japan comes up a lot during the whole World Cup so far. Before every game, we always say what we felt after the Japan match — we say this and we don’t want to feel that way again. That gives us a lot of motivation,” he told AFP.

But du Toit said South Africa would not be partying too long after the victory over Wales.

“I don’t think there’ll be a lot of celebrations. We haven’t won anything so far, so we can’t be too happy,” the 23-year-old said.