The Worcester coach, Anthony Eddy, demanded a major improvement as the Warriors headed for "the big one" - a Pool Five visit to high-flying Clermont Auvergne today.
Worcester cruised past Italian side Viadana, scoring five tries to earn a bonus point, but Eddy was far from satisfied with their error-strewn performance. He knows a repeat will cost them dear this weekend.
Clermont Auvergne are second in the French championship, ahead of European giants Biarritz, Perpignan and Toulouse.
Eddy said: "Clermont will provide us with a totally different challenge. They are the team in form and it is going to be a lot more confrontational and physical over there tomorrow.
"I guess this is the big one. We will have to be a lot more precise at set-pieces, control our possession and not give the ball away cheaply as we did against Viadana.
"I was happy with the win against Viadana but not with the performance.
"It is vital to win your home matches in the European Challenge Cup and we did do that, with a try bonus point, but we turned over a lot of ball and did not really put them under any great pressure. We will need to improve on that."
Harlequins snatched their first win of the season at Connacht last weekend and now hope to catch Montpellier cold at the Stoop today. The French head to London on the back of 21-14 defeat to Bath and Quins' director of rugby, Dean Richards, said: "I think that could mean that they're not as focused, and that might just give us a bit of breathing space.
"Our result has given all the lads and everyone at the club a huge confidence boost. It was even more pleasing because we got the result away from home."
Connacht travel to Bath while Newcastle face Brive without their England centres. Mathew Tait has a torn thigh, though Newcastle insist he will be available for England's game against the All Blacks on 5 November, while Jamie Noon has been rested. Toby Flood, one of seven uncapped players in the England squad, starts at fly-half.
Saracens need an improvement on last weekend's stuttering 28-23 Pool Two victory over Glasgow to trouble their French hosts Narbonne, so their director of rugby, Alan Gaffney, has brought hooker Fabio Ongaro, second-row Tom Ryder and wing Tevita Vaikona into the side.
"We go to France expecting a very tough game," Gaffney said. "Narbonne are not recognised as one of the Premier sides in the top 14, but this season have already beaten Biarritz at home and only narrowly lost at Toulouse a few weeks ago.
Playing any French side at [their] home is a challenging prospect but one we are looking forward to."Reuse content