Leicester director of rugby Richard Cockerill warned the Tigers must go for the kill in Saturday's Heineken Cup showdown with Clermont Auvergne - or it could be their own European ambitions on the slab.
Leicester failed to take their chances in France last weekend and they crashed to a 30-12 defeat. Another setback at Welford Road could prove fatal to their hopes of reaching the quarter-finals. Clermont Auvergne are currently top of pool four - one point ahead of Ulster, who travel to Aironi on Saturday, and two ahead of Leicester.
Cockerill knows Leicester need to bring a ferocity and a cold-blooded ruthlessness to their performance if they are to avoid being cut adrift, and he said: "Last week's match was a tough, full-blooded encounter. It was as intense as any international match and we cannot fall off from that level this week."
He added: "Clermont have an extremely strong squad with quality across the board but the scoreline was not very flattering for us last week.
"We know we have to be much better in terms of accuracy and when you get your chances you have to take them against a top-quality side."
Leicester have brought Thomas Waldrom in at number eight while Boris Stankovich takes over at loosehead prop after Marcos Ayerza was ruled out with a wrist injury.
Clermont Auvergne have suffered a blow after losing Georgia international prop Davit Zirakashvili with a broken arm.
The Tigers are not the only English club facing an uphill battle to reach the knockout stages. Saracens are the only English club top of their pool.
The leading French clubs have a budget around five times greater than the Aviva Premiership salary cap while the Irish provinces are well-funded.
"It's tougher for English clubs to win it now. I think the salary cap has done that," said Bath director of rugby Sir Ian McGeechan. "There has been a big investment in Ireland in their provinces - and in France - so it's no surprise that they are the teams we have to beat."