Glasgow Warriors coach Gregor Townsend admits his side cannot afford a lacklustre start against Exeter Chiefs at Scotstoun on Sunday.
The Scots found themselves 34-0 down at half-time in their opening Heineken Cup fixture against Toulon last Sunday, and though they fought back in the second period to earn a try bonus point, Townsend knows they will need to turn in a complete performance this time around.
And the former-Scotland international says the Chiefs, who hammered Cardiff Blues 44-29 in their first pool game, have impressed him.
"Last week they were outstanding, some of the best rugby I have seen from an English side," Townsend told Sky Sports.
"They were 41-3 up after 50 minutes. They are a very well-drilled side; they know what their game is about. They run the ball more than any other team in England.
"They remind me a lot of Leinster last year. They are very good on the breakdown, they will keep ball and put you under pressure.
"So we have to be switched on defensively, we know we might not get that much ball so we have to make our defence a weapon for us so that we can get the ball back and run with it."
The coach has also insisted his team use the defeat at Stade Felix Mayol as something of a learning curve.
"We learned a great deal last weekend in Toulon, about ourselves and the level of rugby we face in this competition," he added.
"We had gone into the match full of confidence but we were way off our best in the first half.
"The display from our players after half-time was excellent but there is still an underlying feeling in our group of frustration and determination to put things right.
"It is very important that we rise up and deliver an 80-minute performance on Sunday."