Dave Rennie congratulated his Glasgow Warriors for registering the bonus point win they needed to set up a Champions Cup pool decider next week, but the head coach immediately warned them that they must perform considerably better if they are to challenge Saracens.

Their 34-24 victory came at considerable cost, injuries to captain Callum Gibbins and Scotland No.8 Matt Fagerson stretching their back-row resources and they were pushed to the limit by a sub-strength Cardiff Blues side that boasted nothing like the quality of the two-time former champions.

“It’s another couple of rungs up, isn’t it?” Rennie said of the prospect of facing the English Premiership side

“You’ve got to defend really well against them, so we’ll need the same sort of intensity that we played with against them a few months back and be a little bit more clinical with ball in hand than we were that day. We’ve got it in us, we’re looking forward to it.”

Fellow Scots Edinburgh could do them a favour by beating Montpellier on Friday, thereby ensuring that the Warriors have already qualified for the quarter-finals before that meeting with Saracens kicks off, but even if that happens Glasgow need to win to earn the home quarter-final that would enhance their chances of progressing.

“We know it’s a bit of a logjam with Ulster winning yesterday,” said Rennie.

“We think we’ll need more points next weekend. Our mates down the road could do us a favour if they win on Friday night, but we’ve got to go with the mindset that we need to win. Try and win the pool and so on. I think if we prepare that way, we’ll front well. It’s not a bad thing that we still think we need more.”