Guillem Bauza opened the scoring for the Cobblers before Paul Rodgers fired into his own net to level matters, and although Shaun Harrad looked to have won the game from the penalty spot after Andy Halls' foul on Bauza, Greg Tansey's 40-yard drive in the 88th minute earned a point for County.
Johnson said: "It's going to go to the wire, but we've not been dragged under that line yet. It's still in our own hands."
He added: "It was an exciting game because we knew their lifeline depended on it, and ours really, but this was their game where they knew they had to get a win.
"They came back into it and we went ahead again but, to be honest they should have been down to 10 men. I asked the ref and he said Guillem Bauza was running away from goal.
"We get in front again and suddenly a fella (Tansey) hits a 30-yard screamer into the top corner, and whether the keeper's 5ft 6in or 6ft 6in, he wouldn't have got it.
Source: PA
Source: PA