Jim Mallinder was left ruing Saints’ inconsistency after their shock defeat at London Irish.
Mallinder’s men were beaten 25-23 at the Madejski Stadium on Boxing Day after conceding a penalty try two minutes from time.
Former Northampton fly-half Shane Geraghty converted to secure a first Aviva Premiership success of the season for Irish.
For Saints it was a fourth defeat in seven league outings during a campaign in which they have stuttered, having topped the regular-season table last time round.
“We need to start the new year better than we’ve finished this year,” said Mallinder, whose side host Exeter Chiefs on New Year’s Day.
“I guess our form, our position in the league (Saints are fifth with 17 points from seven games) sums up the way we’ve been playing this year: pretty inconsistent.
“You compare this with last week’s passionate performance against a top Racing side and you’ve got to make sure that every single week you bring that full game.
“You’ve got to bring the intensity and the accuracy - and today we didn’t do that.”
Saints had only scored seven tries in the league before the game at Irish, but they did register three at the Madejski.
Ken Pisi, George North and Kahn Fotuali’i all scored as it looked like Mallinder’s men would claim the points at 23-18 up with four minutes to go.
But Jamie Gibson’s sin-binning and referee Ian Tempest’s decision to award a penalty try from a scrum cost them dear.
And Mallinder said: “If we’d have won it we’d have been very happy, but it was always going to be one of those close ones.
“They were pretty dominant in the first half, we came back quite well in the second and increased our physicality.
“We scored a couple of good tries and got on top, but then we lost it.
“They were down to 14 men and we were five points up, but we really just let it slip.”
On the awarding of the penalty try, Mallinder said: “To me, the penalty try was a bit early, but we’re not going to complain about that.
“They’d had a couple of good scrums on us before that and we’re not going to make excuses.
“We need to look at other parts of our game and there’s lots of them that need to improve.
“It’s a lot of the basic things.
“Our discipline has generally been pretty good this season, but you can’t just go giving away soft penalties at lineouts, at scrum, in the tackle area.
“We gave far too many away, which gave them the field position.
“They kept it pretty simple in that they drove well, they ran hard and just did the basics better than us.”