The Welsh region threw pool six wide open with their shock 14-9 victory over the English champions at High Wycombe last Sunday.
But Howells has upped the stakes ahead of Friday’s rematch at Bridgend’s Brewery Field by insisting his team must improve if they are to secure a precious double.
“It’s not a case of asking for the same again because I really didn’t think we played well on Sunday,” said Howells.
“We won that game purely on defence and we showed a lot of guts and character.
“We disrupted their game very well and hit them in areas where I don’t think they have been tested so far.
“But what we didn’t do is show anything in attack and I think that’s what we must do this Friday if we are going to win.”
Howells has named virtually the same team that beat Wasps though is waiting to judge the conditions before deciding on Ceri Sweeney’s half-back partner. Tongan Sililo Martens was replaced by Wales scrum-half Gareth Cooper on Sunday.
“We are expecting a huge reaction from Wasps after that defeat,” said Howells.
“They have made a bold statement with their selection and look an even stronger team than last weekend.
“The return of Stuart Abbott in particular will add another dimension to their midfield.”
Meanwhile the Warriors, who have struggled to attract crowds following the merger between Bridgend and Pontypridd, are anticipating by far their biggest crowd of the season for Friday night’s clash with a near capacity 10,000 expected.
Board member Derrick King said: “We have been inundated with requests for tickets, we can’t sell them quick enough. It’s the most interest we have had for many years.”
Warriors: G Wyatt; D James, S Parker, G Thomas (capt), A Havili; C Sweeney, G Cooper/S Martens; C Loader, M Davies, G Jenkins, B Cockbain, D Jones, M Molitika, R Parks, C Harris. Replacements: M Rees, C Horsman, R Sidoli/N Budgett, N Kelly, N Jenkins, J Bryant, AN Other.
