Saints turned in a real Jekyll and Hyde showing which will leave the fans who witnessed it scratching their heads.
How could they be so, so poor in the first 40 minutes, yet come back to lead the game, only to throw it away at the end?
Halloween may have been earlier in the week, but the Saints players were still doing their best to give their support a few frights.
And Quins took full advantage, capitalising on every slip and every poor Ryan Lamb pass to put themselves in the ascendancy at 21-6 up.
But credit must go to Saints for the comeback they mounted in the second half.
They were, deservedly, subjected to groans from the Franklin’s Gardens during the first half, but after the break, jeers turned to cheers as the tide was well and truly turned and Quins were put under ferocious pressure.
It should have resulted in a precious, morale-boosting win for Jim Mallinder’s men, but opposition fly-half Ben Botica stole it away with the last play of the game.
Again Lamb was guilty of poor decision-making as he kicked away possession with a minute and a half to go - and it cost Saints dear.
The No.10 situation is one which continues to spur debate, but the more immediate issue is the current run of form.
Saturday’s defeat was the fourth in a row in all competitions and fifth in the last six for Northampton. It never rains but it pours.
And Saints will need all the character they have to stop the storm spiralling out of control and bring back the feelgood factor ahead of a big six weeks at home and abroad.
Got himself on the scoresheet and built on a fairly solid showing at full-back against Leicester a week earlier... 6
Had a quiet game and any cries for him to be the man who replaces Vasily Artemyev in the Saints first team might be muted after this... 5
Didn’t do too much wrong on his Saints debut and can look back positively on this one, despite the result. Certainly has real potential... 6
One of the real positives for Saints as he again got on the scoresheet and staked his claim for a return to the Premiership starting line-up... 7
Solid if unspectacular. Played a part in some good second-half moves but is still working his way back to full fitness and expectation must be quelled slightly... 6
Kicked well from the tee but his performance in open play left a lot to be desired. Some shocking passes gave Harlequins impetus and tries... 5
Was not at the level shown at Leicester a week earlier but did get Saints going at points during the second half... 6
Played a big part in Saints’ dominance in the scrum and last season’s young player of the year will be pushing for a Premiership starting place in the next few weeks... 6
Contrasting showing to his steady effort at Leicester during the previous weekend. Handed Harlequins a try with a poor lineout throw and is still learning... 5
Another good performance from the prop, who has improved as the season has gone along. Saints smashed Quins at scrum time and this man was a key component... 6
Another steady if unspectacular performer. Gets the job done but mostly goes unnoticed as he goes about his work... 6
A couple of spills from the back row, who was given a role in the second row for this one. Was replaced with the youthful exhuberance of Teimana Harrison... 5
A second impressive showing in as many games back in the Saints side. His return is such a huge boost for Saints and the skipper tried to drag his team back from the brink... 7
Not a bad effort on his first start of the season. The Saints forwards had a fairly good day, especially during the second half... 6
GERRIT-JAN VAN VELZE
Continues to find his feet in English rugby and can take some positives from this performances... 6