Cardiff Blues coach Dai Young says he fears the "innovative" Scarlets backs as he prepares for the make-or-break Magners League match in Llanelli.
The Blues face missing out on the play-offs if they fail to beat the Scarlets, who could sneak into the top four.
"I think they've probably played the best rugby out of the four Welsh regions," said Young.
"They are very attack-minded and very innovative in a lot of the stuff they've done as well."
The Blues currently occupy fourth place in the table with one game to go, while the Scarlets are three points further back in sixth place.
A victory for Young's side will guarantee them a place in the play-offs, but defeat would open the door for the fifth-placed Ospreys to leapfrog them if they can beat Aironi.
The Scarlets also still have an outside chance of joining the play-off party, knowing that a victory over the Blues and a defeat for the Ospreys would lift them into fourth place.
An opportunity to seal their place in the play-offs slipped through the Blues' fingers last Friday when they lost 28-15 at the Dragons, and Young says their task will be no easier at Parc y Scarlets.
"The Scarlets are quite comfortable to attack from deep so I'm a big fan of the rugby they play down there this season," he said. "We know they are certainly going to challenge our defence.
"Our kicking game has to be spot on - you can't give them ball to run back at you. And we'll certainly have to make sure our defence is solid and taking no dummies.
"They are very elusive players and look to play the game. We've got dominate the game, we've got to control possession and control the field.
"That's not kicking the leather off the ball, but that's playing in the right areas."
Despite having a backline blessed with internationals and creative talent, the Blues have struggled to find their attacking rhythm all season.
They have managed just 35 tries in 21 league games - only the bottom four clubs have scored fewer.
"That's been out weakness all season," admitted Young, who saw his side lose 10-16 to the Scarlets in October.
"We've got the second-best defence in the league, so that's something we've worked hard on. But something that's frustrated us all season is our ability with the ball in hand.
"We have got quality players but for one reason or another it hasn't quite clicked for us."