England meanwhile have their eyes on a first title since 2011 if they can win in the Italian capital and there is a favourable result in Paris between France and Ireland.
And the 26-year-old McLean admits Jacques Brunel's troops will have to stop playing in fits and starts if they want to take down the Red Rose outfit.
"This Six Nations up until now has been disappointing," admitted the 56-cap man.
"Over the last two years the results have been good but if you look back five or six years ago we had some much more difficult times.
"England will be in Rome to try and win the Six Nations, we have to fix things in our game to try and get back to our level for the whole 80 minutes.
"We have not managed to do that in any game in this tournament so far."