The two sides met 24 hours earlier with Assat edging the match 4-3. TPS Turku were eager for revenge and took the lead in the 13th minute of the second period when Arttu Tuhkala struck.
That looked to be enough until less than two minutes of the third period to go, when the Pori side grabbed an equaliser through Johan Olofsson.
The home team took all the momentum into the extra period, and finally broke the TPS resistence after nearly four minutes when Valtteri Lipiainen secured a third win in a row for Assat, while consecutive losses keeps the Turku side in ninth place.
Assat's two points gained further importance given that all the sides immediately below them won. Second-placed JYP needed a pair of third-period goals to put daylight between themselves and KalPa in a 5-2 away win, while Tappara beat Pelicans 2-0 to remain three points further back.
Rounding off the top four are KooKoo who needed overtime for a 3-2 win over Kiekko-Espoo, who have lost further ground on Lukko, who move into fifth with a 5-4 win over SaiPa which saw the Lappeenranta side score three unanswered in the final period and almost complete a dramatic comeback.
Holding onto their place in the top 12 were Ilves who also needed an extra period to beat Hameenlinna - the side immediately above them - 3-2, while the side a place below Ilves, Karpat, heaped more misery on bottom side IFK Helsinki, running out 5-2 winners.
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