The Blues will face a Stormers side determined to lift its defensive effort in the Rebel Sport Super 14 match at Eden Park this evening.

Stormers coach Kobus van der Merwe said defence has been the Stormers' Achilles heel this year.

He told Supersport, "When you analyse the statistics of our game, our defence has consistently been poor. It is not only that we fail in our man on man defence, but also that we do not stop the attacker behind the gain line.

"Our opponents break through the gain line before we stop them and they also have time to pass the ball before we can stop them.

"If you look at the bigger picture of our season this was probably the main reason for our four defeats," he said.

Van der Merwe said there are two problems. The players do not get themselves into the position to execute tackles, and when they do tackle, their tackling is not aggressive enough.

Two sessions in their preparations in Auckland were totally devoted to defensive work.

"We tried to get the message across effectively that defence should be effective and purposeful," he said.

Last night's Crusaders-Waratahs game provided the final lesson and van der Merwe says it is the sort of defensive effort the Stormers will need to contain the dangerous Blues.

The Stormers have suffered an injury with loose forward Joe van Niekerk withdrawing from the game due to a groin injury. He is expected to be fit to play next week.