Yet the win was tarnished by a serious knee injury to loosehead prop Liam O’Connor and the first-half exit of full-back Zebo, while back-rower Jack O’Donoghue ended the game with an apparent shoulder issue.

Zebo had come off with a jarred knee late in the previous week’s win at Zebre but this time he took a bang to his ribs in the first half against Ospreys and was withdrawn at the interval with his new head coach saying the full-back could be sidelined for the back-to-back games against co-pool leaders Leicester, the first of which is at Thomond Park next Saturday night.

“Zeebs we took off as a precautionary measure,” van Graan said. “Last week he had the knee and he took a bang to the ribs. We’ll know more on Monday. It doesn’t look serious. It might be a week or two but I don’t want to speculate at this stage.

“Liam, it looks pretty serious. It’s sad, he’s very important to us in terms of our 23 and going forward, so, again, it looks serious but we’ll know more on Monday.

“At this stage injuries are probably the most negative thing. We’ve got so many guys injured we’ll just have to adapt and stand up and fight.”

The South African, who left his role as the Springboks’ forwards coach to take his first head coach position at Munster, saw the province run in five tries past a ragged and injury-hit Welsh region also missing eight players on Wales duty for their home game against the Boks in Cardiff.

First-half tries from centre Sam Arnold and wing Darren Sweetnam, scored while Ospreys openside Will Jones was in the sin bin, gave the home side an ideal start while flanker Chris Cloete added a third, all of which were converted by Ian Keatley. It helped Munster into a 24-5 lead at the break before Rory Scannell added a fourth to secure the try bonus point inside the first three minutes of the second period.

O’Donoghue scored Munster’s fifth 13 minutes later but was then yellow carded during a spell in which his side conceded six penalties in as many minutes as Ospreys started to pose problems. With a man down, van Graan’s side conceded a 70th minute try to Will Jones, but it was a mere token on a night dominated by Munster.

Asked what had impressed him about the performance, van Graan replied: “Composure. I thought this was going to be a difficult game for us with Europe looming.

“We played against a team that were desperate and I thought we started really well. For the first 36 minutes we were very clinical and then at half-time we assessed what went well and what didn’t and then we scored that brilliant try just after half-time.

“I thought some of those young backs performed very well tonight. Very happy with Sam Arnold, Calvin Nash coming on. JJ (Hanrahan) played well (having replaced Zebo), I thought Keats played the territory game very well. Duncan (Williams) coming back and also I thought James Hart had a very good 50 minutes.

“Some great tries. I thought we can still improve our set-piece and we left some chances out on the field but in general, pretty happy.”