Munster head coach Johann van Graan spoke of his frustration with a couple of "unacceptable" late tackles on young fly-half Ben Healy in their 21-7 Heineken Champions Cup Pool B victory over Harlequins at Thomond Park.

Alex Dombrandt was yellow carded for a shoulder charge on Healy in the 62nd minute, and the 21-year-old is now an injury doubt for next Saturday's trip to Clermont Auvergne.

"We're very worried about Ben, he took two late hits there," insisted van Graan.

"We're going to get him checked out now. It was quite clearly a tactic from the opposition to hit him late and certain things in the game are just unacceptable. He's now got injured because of that."

While Quins were tough opponents, the second round clash with Clermont will require Munster to be at their best. The Top 14 side defeated Bristol 51-38 in a sparkling start to the tournament - but van Graan very much welcomes the challenge ahead.

"Clermont are one of the European powerhouses if you look historically. Some big tussles between Munster and Clermont. If you looked at them yesterday, they were excellent the way they started against Bristol.

"It's a massive challenge ahead for us and that's what this competition is about, to challenge yourself against the best teams.

"It's great that Munster and Clermont will go out with their top teams because this is what the competition is about. You always want to play your top teams in this competition," he added.