England captain Steve Borthwick tries to power through the Italy defence
Martin Johnson has warned his England players they must be ready for an extremely intense examination when they face Wales in Cardiff next week.
England beat Italy 36-11 in their RBS Six Nations opener but the scoreline flattered the hosts, who scored five tries, three from Italian errors.
"Cardiff will be a real eye-opener for some of the younger guys," said the England manager.
"It will be a ferocious game and they will have to keep their composure."
England were put under little pressure by Italy at Twickenham until the visitors replaced makeshift scrum-half Mauro Bergamasco at half-time.
But Johnson's men still conceded 13 penalties, 10 in the first half, and had James Haskell and Shane Geraghty sin-binned for a subtle trip and taking a player out in the air, respectively.
We're the underdogs, we've got nothing to lose, and we've got to make sure we front up
England flanker James Haskell
Flanker Haskell conceded England would need to be more combative to trouble Wales, the only northern hemisphere side to beat a Tri-Nations side in the autumn and the favourites to retain their Six Nations title.
"The atmosphere [at the Millennium Stadium] is incredible," said the Wasps man. "When people ask if I notice the crowd in the game, I usually say no, but in Cardiff you do, especially when Wales are going forward because it's so loud.
"But we're the underdogs, we've got nothing to lose, and we've got to make sure we front up. We need aggression and competitiveness at the breakdown, because Wales have got some big ball-carriers and if you back off and allow them to play you get badly burnt.
"But I would never take to the field thinking I couldn't beat a team we were playing against. The autumn internationals had an effect on us but as soon as the Six Nations started we stopped feeling sorry for ourselves, worked very hard, and we'll take a nothing-to-lose attitude to Wales."
England skipper Steve Borthwick said England will have to "perform very, very well" and make fewer mistakes if they are to compete in Cardiff.
"We've got to improve from here to next week and we have to ensure we don't make the same mistakes next week," said the Saracens lock.
"It's a great challenge for us to go down to the Millennium Stadium. We'll study the videos and work hard to make sure we're a better side than we were this week.
"We know that Wales are a fantastic team, so we know we're going to have to perform very, very well. We need to improve and we will."