"This is the make or break match for us - without a doubt the biggest and most important game of our season so far," said Gloucester's England back row forward Luke Narraway, who has played in all four of their Pool matches so far and scored tries in both legs of their double over Rugby Calvisano.
"If we lose that will be us very much out of the Heineken Cup but win on Sunday and we will still be right there in the mix with a tough game at Biarritz Olympique to come in Round 6.
"The big thing is that our fate is totally in our own hands, it is up to us to go on and qualify for the quarter-finals and to do that we have to start with a victory against the Blues on Sunday and then repeat that over in Biarritz five days later."
"Having the match at Kingsholm is a huge thing for us," said Narraway. "The best club crowd I have played in front of was the one at Kingsholm for the Munster quarter-final tie last season and I see Sunday as having much the same sort of atmosphere with most of the 16,500 crowd roaring us on.
"The Round 2 match at the Millennium Stadium was magic as a spectacle - it was my first time as a player at the Millennium - the stadium and crowd were just unbelievable - but our rugby was not the best.
"We were pretty sloppy, and it was disappointing that we gave them so much of the game, including a valuable try bonus point.
"So the first thing on Sunday is to look for the win and then, if we can play some decent rugby, perhaps push on and earn the bonus point.
"However, the Blues are a great side with so many great players - the Welsh regions have certainly benefited from having their leading players with just the four sides - so it is hard to single out individual threats as their squad is almost entirely international players.
"But Andy Powell has come on really powerfully and played some great rugby so we will need to stop their strong runners like him while being well aware of the dangerous players they have in the backs.
"As for Gloucester, our season has been a bit of hit and miss - we have played well in some matches and then let ourselves down in others - like last weekend's 10-7 defeat at Newcastle Falcons which means we have lost five of our 19 games so far this season."