Tappara had to do it the hard way, as Pekka Jormakka and Valtteri Ojantakanen put opponents JYP 2-0 up after 20 minutes, but a pair of powerplay strikes from Oiva Keskinen and Jyrki Jokipakka had drawn them level again by the end of the second period.
Neither side could find a crucial third goal in the latter stages of regulation, but one finally came two minutes into overtime, as Joachim Blichfeld completed the turnaround, 3-2, and ensure Tappara will play in the Champions Hockey League next season.
Despite the loss, JYP's lead over the sides chasing their fourth place has increased to two points over Ilves - who weren't in action last night - as both Lukko and KalPa were defeated.
Lukko thought they had saved themselves when Derek Daschke levelled their match with Kiekko-Espoo with just five seconds to play, but after no overtime goal, John Stevens' penalty won the shootout for KE for their third win in four, as Lukko's first loss in three could only draw them level on points with Ilves.
KalPa's night was worse - they conceded three unanswered goals in the third period to lose 4-1 at home to IFK Helsinki. The champions stay in seventh, three points of JYP having played a game more than all their rivals. Three successive wins have put HIFK on the brink of the playoffs.
A match against cut-adrift Vaasan Sport was the perfect tonic for TPS Turku to end a four-game losing run with a 3-0 victory that takes them to just a point behind Hameenlinna in the race for 12th. Eetu Makiniemi made 16 saves in the shutout, as Sport lost their 18th game in a row.
Second-placed SaiPa failed to secure their place in the top four, while Pelicans all but wrapped up their place in the postseason after a 4-1 final score in Lahti that keeps them nine points clear of 13th place with a first win in three, while it's a first loss in three for SaiPa, meaning of the five sides in the top half all to play last night, only Tappara emerged victorious.
Follow the finale to the Liiga regular season on Flashscore.