Munster became the first side to qualify for the quarter-finals at the weekend with victory over Castres but director of rugby Tony McGahan still reckons his side need to improve.
The former Heineken Cup Champions beat Castres 26-10 at Thomond Park to keep up their unbeaten record in this year's competition.
They travel to Milton Keynes next Saturday to face Northampton Saints and McGahan believes his side must improve as the Saints will be looking for revenge.
"I thought we worked extremely hard to put ourselves in good positions, but the final pass and ruck detracted from the end product we were looking for," he said.
"There is no hiding from it, we certainly need to improve in that area.
"What was poor was the handling on the end of things more than the positions we got ourselves in.
"I think Northampton will be looking for revenge.
"They made their thoughts well known when they left here and it certainly stayed with them for the rest of the week against the Scarlets.
"I think the way they have attacked the Aviva Premiership and the Heineken Cup games, we are certainly in for a great battle next weekend."