Pat Lam says he wants Bristol to be a club that "goes after the trophy" when they rejoin the elite of European club rugby.
Bristol will end a 12-year wait for top-flight European action on Saturday, kicking off their Heineken Champions Cup campaign against French heavyweights Clermont Auvergne at Ashton Gate.
A different format this season sees 24 teams featuring in two pools of 12, with the top four in each group – each club plays two opponents home and away – securing quarter-final status.
And Bristol rugby director Lam is relishing tackling a tournament that leaves little margin for error in terms of last-eight ambitions.
"As I've said to the players, the competition is not up there to be in it, it's up there to compete in and try to win it," he said.
"The goal is to get stars on that Bears jersey.
"I don't want us to be a club that just gets into Europe and is happy to be in it. We have got to be a club that goes after the trophy."
Although Clermont have never been crowned European champions, they featured in three finals between 2013 and 2017.
Lam added: "Clermont have got the history and the experience of playing in this competition. They have been there or thereabouts every year, so they have that on their side.
"The reality is there are some unbelievable clubs in this competition, and you could win four games, finish fifth in the group and not make it through.
"When you have got the best of the best, you have to be at your best.
"If you lose a game, the chances of you getting through are very remote because of the quality of teams that are involved. It puts an edge straightaway."
Diamond unexpectedly departed his post as rugby director earlier this week, leaving head coach Paul Deacon in charge for what is a testing tournament opener.
Asked if Diamond going would impact the squad, Deacon told Sale's official website: "I can't say for certain whether it will or it won't.
"It is new to all of us and we have just got to crack on. We aren't changing much, we are doing what we always have done, so we will see what happens this weekend."
Bath have only reached the quarter-finals once since 2009 and they have a tough first game at home to Scarlets, who destroyed the west country club 35-17 on their last European visit to the Recreation Ground two years ago.
Bath welcome back the likes of Anthony Watson, Jonathan Joseph and Sam Underhill from England Autumn Nations Cup duty, but fly-half Rhys Priestland is sidelined after suffering a head injury against Worcester last weekend and is replaced by Josh Matavesi.
Scarlets are without injured Wales backs Liam Williams and Johnny Williams, and head coach Glenn Delaney said: "Unfortunately, a few boys have come back from Wales camp with injuries, and we will continue to monitor and assess them over the coming weeks.
"We love this competition, we want to go well in it and really give a good account of ourselves."
Wasps, bolstered by the returning Dan Robson, Joe Launchbury, Will Rowlands and Jack Willis, open up against the Dragons in Newport, where Charlie Atkinson takes over from injured fly-half Jacob Umaga.
Reigning European champions Exeter, meanwhile, begin their title defence with a Sandy Park clash against Glasgow on Sunday, with Gloucester also in action – away to Lyon – Harlequins visiting Munster and Racing 92 hosting Connacht.