But rookie fly-half Pienaar reckons performances are vital ahead of the clash with Ian McGeechan's men on home soil.
"We're building for the Lions tour and we need to prove ourselves in every game," said Pienaar.
"I've been involved in a World Cup but now my goal is the Lions.
"They only visit South Africa once every 12 years and there is a massive opportunity to be part of the Springbok squad to play them."
There were doubts over whether the Sharks utility back could handle the pressure in a new position after spells at scrum-half and full-back, but Pienaar passed his first test with flying colours in Cardiff.
"I'm used to the pressure and without doubt I can handle it," added Pienaar.
"There is more responsibility on me at No10 and I'm having to lead the line on defence and spot opportunities to attack. In the past I'd be nervous before big games but I'm a more relaxed person now.
"Playing at fly-half is a new challenge but I've got confidence and self-belief in my own ability. I just try to focus on the basics and what I need to do."