Manchester City ran out 2-1 winners on Saturday at Old Trafford.
Neville told Sky Sports: "The build-up to the game was probably the biggest I've ever seen to what would be, in my eyes, a normal league game - obviously there have been title deciders between these two sides in previous years at the end of the season.
"This is a game four or five games into the season, and the build-up was huge. Subconsciously, we wondered whether the managers would think: 'Let's get out of here without damage.'
"Many predicted a draw, but it was absolutely nothing like I expected, it was the game you would have dreamt of in terms of end-to-end, punch-for-punch, both managers having to make substitutes and having to retreat. It really has been a wonderful occasion."