Playing away from home against the seven-time champions means the Pretoria outfit are the overwhelming underdogs, but the Springbok number eight is confident his side can cause an upset.

"Quarterfinal rugby is about how you handle pressure and how you exude pressure," said Spies.

"It is obviously a challenge to play the Crusaders at home but we are looking past that."

The last encounter between the two sides was a battle of attrition, with the Bulls narrowly edging the Crusaders 32-30 at Loftus Versfeld in Round Seven of the competition.

A small storm, however, erupted afterwards over two eye-gouging allegations that were made against the Crusaders. The claims have since been refuted and the Bulls were adamant this week they had buried the hatchet.

"We've already played against them this year and it will be a tough game but we are backing ourselves," said Spies.

The 27-year-old said the return of a seasoned player like Flip van der Merwe from injury gave his side a timely boost ahead of the crunch clash.

"You have to use every bit of experience and the players who have it must bring it to the fore," revealed Spies.

"It is important that it counts in your favour on the day.

"We have enough experience in the team and it is a great challenge to us as a group."

Bulls coach Frans Ludeke added his players were aware of the extent of the challenge they faced against Super Rugby's most successful side.

"They are a good team, we respect them and we know their ability," said Ludeke.

"They have shown throughout the year on a number of occasions that if you allow them to get momentum they can make it difficult for you."