Cobblers boss Keith Curle made no excuses for his side's 3-1 defeat to Cheltenham Town on Saturday, admitting their performance fell well below recent high standards.
Town's eight-game winning run came to a crashing end at Whaddon Road as Luke Varney bagged a first-half brace to put Cheltenham on course for a sixth home victory in their past seven matches.
Tyrone Barnett headed in a third with 17 minutes to go before Dean Bowditch's last-minute free-kick gave Cobblers fans something to cheer, but it came far too late to affect the outcome.
Beaten for the first time since February 2, Town's hopes of sneaking into the play-offs this season looking increasingly remote, particularly after Exeter City moved nine points clear with a last-gasp win at Notts County.
"I thought the performance today wasn't us," admitted Curle, who was without Jordan Turnbull and Aaron Pierre at Whaddon Road. "We didn't start the game how we needed to start it because we needed to put them on the back foot.
"They have a very good home record and they have a way of playing that we needed to nullify, but we didn't nullify them and too many players made the wrong decisions at the wrong times for the betterment of themselves and not what we've been trying to do."
Sam Foley and Charlie Goode were among players to make costly errors in the first 45 minutes as the Robins charged into a two-goal lead.
"If you don't do what needs to be done when it needs to be done, you end up giving a team a two-goal headstart and that's what we did today," continued Curle.
"If you make the wrong decisions in the wrong areas, you'll get punished. The tempo wasn't there, the urgency wasn't there and the decision-making wasn't spot on."