The Millers took a fifth-minute lead when Nicky Law's shot was deflected past his own goalkeeper by Paul Rodgers. Jason Taylor doubled their advantage on the stroke of half-time, but Cobblers substitute Leon McKenzie pulled one back and Davis struck through a crowded box to send the Sixfields crowd wild.
Johnson said: "The players and supporters showed great character and it was a fantastic fightback to come back from 2-0 down at half-time.
"I had to get angry with the players at half-time because in the first half it was men against boys, Rotherham won everything and my players looked like rabbits in car headlights.
"But they showed me in the second half what they can do and we deserved a point for the way we fought back. But they shouldn't have to wait until half-time to be mentally prepared for a game like that.
"I had to make changes at half-time and with Leon McKenzie, although he's not ready to play a full game, you know what you're going to get with him and he always seems to be in the right place in the box."
Source: PA
Source: PA