Double winners to Champions Cup whipping boys in little more than two and a half years.
That is the sorry state Saints have found themselves in, with their Pool 4 hopes having gone up in smoke in dramatic fashion.
Since beating Montpellier with the final kick of the game on the opening night of the European campaign, Saints have shipped an eye-watering 138 points.
They were crushed in Castres, ground into the Franklin's Gardens turf by Leinster and then systematically disemboweled in Dublin.
It has been horrible to watch.
A proud club has been dragged along, like Achilles pulling Hector's lifeless body along with his chariot.
And while Saints had given up on qualifying for the quarter-finals by the time they entered the Aviva Stadium, that cannot mask the first two Champions Cup defeats they suffered.
And it cannot hide the fact that they utterly capitulated in Ireland.
They looked like they were about to produce one of those trademark stirring responses when they flew into a 13-5 lead after 21 minutes at the Aviva Stadium.
The forwards got on top, bossing the breakdown, and at a surprisingly subdued Aviva Stadium, it was Northampton voices being heard.
Supporters who had looked at the team selection with trepidation - Mallinder opted to make 10 changes, leaving out a host of international stars - were stunned.
Smiles were on the faces of the fans who forked out hundreds of pounds to watch their side, without knowing at the time who would be wearing the white shirts.
But in the end, the men in white coats were needed, as Leinster inflicted serious mental torture.
When Leinster got back in front, Saints, hit by injuries to Ahsee Tuala, Calum Clark and George Pisi, were unable to summon any sort of response.
And young guns such as Charlie Clare, Rory Hutchinson and James Fish were ultimately lambs to the slaughter.
Forget the stuff about this being good experience for them, it was not a good experience for anyone of a Northampton persuasion.
But while you could feel sorry for those young men, the ones who really deserved sympathy were the supporters.
Because while Saints folded like a cheap suit, conceding nine tries, the travelling faithful continued to sing.
They were determined to make the most of their trip.
But unfortunately, they are having to find enjoyment at the bottom of a pint glass rather than on the rugby field right now.
Their team is a shadow of the one which won the Aviva Premiership and Amlin Challenge Cup in an incredible, indellible 2013/14 campaign.
The class, composure and resilience of that special season has not been on show during this torrid transformation.
And with plenty of contracts coming to an end, there will have to be a major overhaul next summer.
Players appear to have peaked a couple of years ago and there has been little transition since.
In fact, if you were to select Saints' current first-choice side, the majority of the men were in that double-winning squad.
There is a recognition that change is required and that the club has evolved slower than the caveman.
However, with performances such as the one on Saturday night comes doubt for players joining the club.
Do they want to be part of this?
Well, Saints have got plenty of persuading to do over the next few weeks, and it starts with cold, hard scorelines.
Mallinder's decision to make so many alterations - it has to be said that there was still a starting 15 full of first-team squad members on show in Dublin - has cranked up the heat.
Saints are now heading for a Heineken in the last chance saloon and simply have to win the next three league games.
That was clearly the target when the Champions Cup bid was sacrificed on Saturday.
Mallinder said as much before and after the game.
But there is no wriggle room left now.
Must-win matches, week after week.
Saints will have to show they can respond how they used to in the days when silverware came their way.
They must show their fans that they still have the ability and passion in them.
Unfortunately, memories of the dark night in Dublin and the other European defeats this season will linger.
Heads will be spinning at all levels at the Gardens.
And if things don't improve this week, the hangover could be felt long after Christmas.
How they rated...
Injured himself in trying to keep up with Ken Pisi for Saints' only try of the night, and he didn't have to be part of the nightmare that unfolded soon after... 6
Managed to grab a breakaway try, sprinting from inside his own 22 to score, but that was as good as it got and he handed Leinster a try in the second half... 4
A night to forget for the Samoan centre, who fumbled to give Leinster a breakway try and dislocated his shoulder meaning he had to come off at half-time... 4
Was passed fit for this game, but even though he got stuck in, he probably ended up wishing he had missed out as Saints toiled in the second half... 4
Enjoyed a memorable night at the Aviva Stadium three years ago, but this was the polar opposite as Leinster ran riot... 4
Kicked eight points to put Saints ahead, but it went downhill after that as he was consigned to doing a defensive role... 4
A really bad night for the scrum-half, who saw two box kicks charged down during the first-half and who was unable to do anything in attack... 3
Gave it his all, but Saints were eventually totally overwhelmed up front as Leinster tore them to pieces... 4
Would have been looking forward to testing himself against the best, but this was not the night for it... 4
Returned from his two-week suspension and didn't have any joy as Leinster walked around Saints' forwards...4
Disrupted Leinster's lineout once in the first half, but was probably glad to be taken off 12 minutes into the second half as the blue tide washed over Saints... 4
Carried well in the opening exchanges, but it was constant defending after that and a really draining night to be a forward... 4
Made plenty of tackles, but became the latest Saints player to be yellow carded as he headed off for a spell in the sin bin during a sobering second half... 4
Like Harrison, he relished the opening stages of the game, but his night was cut short by injury... 5
Really took control in the opening 21 minutes, turning the ball over superbly, but things soon took a turn for the worse... 5
Replacements (who played more than 20 minutes)
JAMES WILSON (for Tuala 23)
A horrible night to be a full-back as wave after wave of pressure came his way and he was often left helpless... 3
BEN NUTLEY (for Clark 40)
Was unable to chop Leinster's big runners down as the home side simply waltzed through Saints in the second half... 3
RORY HUTCHINSON (for G Pisi 41)
Not a nice night for the youngster to be part of because although he tried his best, Leinster's men were too good for Saints' boys... 3
PAUL HILL (for Brookes 52)
Tried to help Saints at least front up physically, but the damage had been done and Leinster were relentless... 3
MICHAEL PATERSON (for Craig 52)
May have come on with only 28 minutes to go, but Leinster were to score four tries during that time and the forwards were left feeling powerless... 3
CHRON STAR MAN - Isa Nacewa (Leinster)