Boss Jimmy Floyd Hasselbaink believes the Cobblers’ issues with inconsistency is a ‘psychological’ problem.
Town travel to in-form Portsmouth on Saturday aiming to shrug off their disappointing 3-0 defeat at Doncaster Rovers on Boxing Day.
That result followed encouraging performances in the previous two games, with Walsall being beaten and Blackburn being held to a Sixfields draw on Saturday.
But plenty of old bad habits resurfaced at the Keepmoat Stadium, and Hasselbaink said: “I think it’s a psychological thing and a mind thing.
“We need to stop thinking that we are already there, we need to keep on working and keep on improving.
“Even though we have played really well against two good sides, that’s forgotten about and you have to start all over again and we didn’t on Tuesday.
“We have retained the ball a lot better. I felt like we were always under pressure and always wanted to pass with the first touch.
“Take your time, at times you have more time than you think and you can use two or three touches instead of one touch and that was the difference.”
One area where the Cobblers have some unwelcome consistency is their results on the road.
Town have lost their past five away games in all competitions, and have conceded eight goals in the past two, which saw them hammered at 5-1 at Oldham Athletic and 3-0 at Doncaster.
They last avoided defeat away from Sixfields when they saw off Oxford United 2-1 back on November 11, and Hasselbaink feels that performance proves that the team’s problems on the road are something that can be rectified.
“We’ve shown in some matches away from home,” said the Town boss. “We had a spell where we were actually better away than we were at home.
“On Tuesday at Doncaster, I don’t know what happened and I will have to look back at the video and have a think but before the match I thought we were fired up.
“We gave them a little bit too much respect.”
For the testing looking trip to Fratton Park, the Cobblers will at least be boosted by the return of midfielder Matt Crooks, who has now served his two-match suspension.
But Town are still likely to be without central defenders Aaron Pierre and Leon Barnett through injury, while Daniel Powell, Aaron Phillips and Alex Revell are all set to miss out.