WALES have been warned that they must not allow South Africa master tactician Fourie du Preez to enjoy an armchair ride if they are to triumph in Saturday's World Cup quarter-final.

The 33-year-old will skipper the Springboks in the clash at Twickenham after helping them overcome their shock loss to Japan on opening weekend to qualify for the last eight.

Du Preez missed the Rugby Championship through injury and was only a replacement against the Brave Blossoms but has pulled the strings in the wins against Samoa, USA and Scotland.

And Newport Gwent Dragons lock Rynard Landman, who headed to Rodney Parade from the Cheetahs, says Warren Gatland's pack have to stand firm against the Boks' power runners if they stop the 2007 World Cup winner giving them the runaround.

"Du Preez is the master of the attack and like red wine is getting better with age," said Landman.

"He was missed before the World Cup and in the first game. Ruan Pienaar is a class player who performs well for Ulster but Du Preez speeds everything up and his decision-making is so good with great vision."

Welsh fans looking for good omens will be pleased that Landman is once again missing seeing his compatriots take on his adopted nation because he is on club duty in Glasgow.

Last autumn he watched on with dismay in Scotland as the Boks were beaten 12-6 in a tense clash at the Millennium Stadium. Landman says the same blueprint will be needed at Twickenham.

"Wales put heat on South Africa's rucks and slowed ball down to stop their big ball carriers getting momentum coming around the corner," he said.

"The Springboks have big forwards who like to dominate the set piece, getting over the advantage line from first and second phase then Damian de Allende, Bryan Habana and the speedsters can create some magic behind

"But it all starts with forward momentum. Give them slow ruck ball and you will always be in with a chance.

"Wales need to get off the line quickly in defence and kill South Africa's momentum, then anything can happen in quarter-final rugby."