The Northampton winger is adamant that the way Stuart Lancaster's side clawed their way back into the game after trailing 17-3 in the first half is a feat few sides could match.
Ashton is quoted by Clubcall as saying: "I think they've just got that little bit of class ahead – [Ma'a] Nonu's offload for the [Julian] Savea try was unbelievable for them to win the game - and I think they showed again on the weekend [against Ireland] why they are the best team.
"But I don't think we are too far away from them. Of course we'll be disappointed with the loss - but overall I think we'll be very happy with how the three games went."
England are currently fourth in the IRB world rankings, behind the All Blacks, South Africa and Australia.