The tempo and accuracy of the Springbok game have improved since the veteran of 73 tests was drafted back into the side, probably before he was quite ready, following long-term injury.
Ruan Pienaar, much maligned in South Africa for a perceived dithering approach to scrumhalf play, started the disastrous 34-32 loss to Japan in the Boks' tournament opener.
But since being rushed back into service, Du Preez has been a central figure in back-to-back wins over Samoa and Scotland that have put South Africa’s destiny in their own hands as they sit on top of Pool B with their final match against the USA on Wednesday.
It is his decision-making, and speed of thought and movement that makes the side tick, igniting a backline with plenty of potential when on the front-foot.
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It is a point not missed by Bok coach Heyneke Meyer after their 34-16 victory over Scotland on Saturday.
"I think we've still got a lot to work on but I have to give Fourie a lot of credit; he was brilliant today," Meyer said in picking out his number nine, who he handed the captain’s armband to in the absence of Jean de Villiers, now out of the tournament, and Victor Matfield.
"Fourie kept the guys calm. He ensured the team stuck to the plan and really managed that 10-12-13 combination well."
Du Preez, quiet and unassuming off the pitch, admits to nerves despite his experience in winning the 2007 World Cup in France where he also played a key role.
"I haven’t felt pressure like this before," he said of the week leading up to the Scotland game. "I'd say there’s been more pressure on us now than there was in that 2007 World Cup final.
"We had to slow down the game, and really grind out the result (against Scotland). We had a lot to lose in this fixture."
(Reporting by Nick Said; Editing by Amlan Chakraborty)
