The Italians were pressing hard for a second try right up to the end and no one could have complained if they had earned a draw or more from their performance. But having 'won ugly', Chris Robshaw's men will get a shot at a potential first Grand Slam since 2003 at the Millennium Stadium.
"We know we have to improve our performance going into the Wales game. Nobody is punching the air in the changing room. We know we can do better," admitted Lancaster.
"If we'd won easily, there may have been an element of complacency or over-confidence seeping in. There won't be any of that. We know we have got to play better, we know Wales are playing well but equally we know what we need to do to fix things up and we are confident in the players we've got.
"We've still got a young team and we need to be a little bit more composed in key areas. That composure will be tested at the highest level on Saturday."