By beating SJK a week earlier, Mariehamn finally registered a win this season at the 20th time of asking, but an away trip to champions and league leaders KuPS would provide a much tougher test, even if they did pick up a rare point at home in the reverse fixture.
As it turned out, it was a test the Aland islanders were ready for - they took the lead in some style in the sixth minute, when Adam Larsson took aim from 25 yards and leathered the bouncing ball into the top corner.
The lead lasted all of five minutes, as Gustav Engvall drew the home side level, but the early goal-fest continued, as Jonanthan Svedberg turned provider to scorer and restored the visitor's advantage in the 14th minute.
Before half-time, the shock factor grew as Mariehamn opened a two-goal lead - KuPS were powerless to stop Ludvig Richter, who surged down the right wing, cut into the box and gave Johannes Kreidl no chance with his finish.
It was game on again just before the hour mark, as Clinton Antwi found Piotr Parzyszek to score for the second time this week after netting against Shamrock Rovers, but again parity was short-lived, as the side at the foot of the standings scored their fourth just three minutes later, as Richter completed his brace.
Mariehamn saw out the victory from there, meaning the six points from their last two games is more than the total they amassed in their first 19. For KuPS, it's just a second league defeat of the season.
Gnistan came from 2-0 down to earn an unlikely victory in the Helsinki derby away at HJK which not only secures their place in the championship group, but takes them above their neighbours into third.
The visitors looked set for a nervy final day when they found themselves two down at the break - Santeri Haarala found the empty net after goalkeeper Matej Juricka and forward Mads Borchers collided, before Ville Tikkanen slammed the second into the top corner to complete a free-kick routine.
With a quarter of the match to go, Adeleke Akinyemi raced away to pull one back, and seven minutes from time his header from a Bogdan Milovanov cross had Gnistan level.
And in the 89th minute, pressure from Akinyemi forced a turnover in HJK territory, before Danny Perez forced a mix-up between his marker and goalkeeper Matej Markovic, and Perez rolled the ball into the empty net to complete the turnaround for Gnistan.
Back-to-back wins see Gnistan move within eight points of leaders KuPS, with HJK a point further back as their own two-game win streak came to an end.
The Turku derby was unable to live up to the entertainment levels of the day's other two matches, as TPS hosted a goalless draw, meaning Inter Turku couldn't take full advantage of KuPS' loss, only cutting the gap at the top to four points.
TPS will have to beat Gnistan on the final day of the regular season and hope AC Oulu lose to SJK if they are to snatch the final championship group place, but they are fortunate still to have a chance after they had Kian Visser sent off in the 62nd minute for elbowing his marker in an off-the-ball incident.
While there were no goals, the heated exchanges continued beyond the final whistle, as both side extended their unbeaten runs to four games.