The defeat ended a three-game winning run, but was a great improvement on the previous outing at Dronfield, except for the final outcome.
The Red and Greens went ahead from a second penalty-induced lineout in quick succession.
From it, the backs were released and Paul Gutteridge cut a superb line from centre to slice open the Huntingdon defence and dot down close to the posts. But Meehal Grint’s conversion attempt drifted wide.
Captain Chris Starling was sinbinned for a trip which sparked a spell of Huntingdon pressure, and when Ben Chamberlin was penalised for going off his feet, Stags fly-half Dan Malem kicked the penalty to make it 5-3.
The visitors went in front when winger Tom Morgan was held up over the line after a strong run, and from the five-metre scrum, Glen McIntyre picked up and powered over.
Malem added the conversion before Rasen and Louth were restored to their full complement and hit back.
From the restart, the Red and Greens secured possession and drove into Huntingdon’s 22.
Fly-half Dan Robinson’s astute cross-field kick caught the visitors unawares as Gutteridge claimed the ball in sight of the line. Huntingdon scrambled back, but a superb sleight of hand saw Gutteridge pop a pass for the supporting Tom Stephens to gather and level the scores.
Further indiscretions allowed Huntingdon to restore their lead when another penalty kick to touch allowed prop Luke Murphy to barrel his way over from the lineout.
But Rasen and Louth bounced back almost immediately as number eight Dave Starling burst clear and delivered a sublime pass for Chamberlin to sprint over the line. Grint landed the conversion to give Rasen a slender 17–15 half-time lead.
Huntingdon started the second half on top, and Rasen were shown another yellow card when Adam Dearden was binned for 10 minutes.
But the hosts held out when the Stags kicked the penalty to touch and carved out a chance of their own.
Stephens who set off down the wing and powered his way past several would-be tacklers before he was eventually stopped.
The forwards took over, and an illegal intervention earned Seth Muggeridge a 10-minute break as Rasen and Louth were awarded a penalty.
With the sides now equal in number, the Red and Greens opted for the scrum and moved Dave Starling into the backline.
It turned out to be a masterstroke as possession was secured and Dave Haig’s delayed pass put Dave Starling clean through a gap to secure a try bonus point.
The game was still poised on a knife edge as it entered the final quarter, but Rasen and Louth suffered a mini implosion.
Dave Starling was sin-binned for interfering with a quickly-taken penalty and then the defence switched off, allowing Malem to glide through a gap to score under the posts. The simple conversion drew the sides level again.
Malem then kicked a penalty to restore the visitors’ lead, and four minutes later Huntingdon made sure of the win when Simon Rose sprinted down the touchline to score in the corner.