Defender Michael Harriman says the Cobblers are still very much in the play off semi final with Cheltenham Town ahead of Monday's second leg at the Jonny Rocks Stadium.
Cheltenham have a 2-0 advantage from Thursday's first leg, but Harriman says the Cobblers will travel to Gloucestershire with hopes of turning things around.
"Thursday wasn't a great night but we are still in this game," he said.
"There are 90 minutes to go and as we all know, 2-0 is a horrible scoreline to defend. We will go there on Monday, give it everything we have got and if we can get the first goal on the night then everything changes.
"We had plenty of opportunities on Thursday. The penalty save was obviously a key moment, and it was a game of opportunities. We didn't take ours, they took theirs and fair play to them.
"Penalty misses happen. Ryan (Watson) scored against Plymouth earlier in the season but on Thursday their keeper made a good save. He's allowed to do that and that is what happens sometimes. We are not out of this game, we will go there on Monday and give it everything.
"The first goal on Monday could change everything. Our approach is clear, we have to win well there. It will be tough but anything is possible in football, particularly in the play offs."