After losses in the opening two matches, the pressure was all on Tappara for game three at home, which they revelled in, grinding out a 2-0 win and giving them the chance to level the series in Kouvola in game four.
Eetu Tuulola was called for tripping early on, but after his teammates survived the KooKoo powerplay, he more than made amends with eight minutes gone, tucking away a simple finish after great work from Kasper Simontaival to maintain possession and thread a wonderful pass through.
Soon after, Simontaival was denied a goal of his own following a successful coach's challenge, but Tappara needed only wait another minute to double their lead, as Benjamin Rautiainen worked brilliantly behind the net before finding Joachim Blichfeld, whose shot squeezed through the goaltender.
But KooKoo proved they were up for the fight with still over three minutes of the first period to play, halving the deficit when Jiri Parssinen's shot caused havoc in front of the Tappara goal, before Manu Makela emerged with the decisive touch to force it home.
Neither side were able to make use of a powerplay during a second period which for a long time saw the Battle Axe preserve their narrow lead, until the final two minutes when Joonas Oden intercepted a loose puck in his own zone and skated away to fire in the equaliser.
Tempers began to flare in period three, as both teams had two players sent to the box for fighting, but when Jonathan Andersson was called for high sticking with five minutes to go, KooKoo were unable to complete the turnaround, and overtime was needed.
Incredibly, OT was almost done and dusted within two minutes, but this time it was KooKoo's turn to have a goal disallowed after another successful challenge, this time against Joseph Berger. But instead, the match went on and on, as three period of overtime went by without a winner.
Assat needed four overtime periods to beat SaiPa at the very beginning of the postseason. That 125-minute match set the Liiga record, but these two teams surpassed that tonight, as Christian Heljanko made 57 saves, while Eetu Randelin responded with 49.
But crucially, Randelin wasn't able to bring up a half century - approaching the end of the 130th minute, Kristian Tanus played a wonderful reverse pass from behind the net, and Oiva Keskinen did just enough to find the gap between the KooKoo goalie and his near post to win it 3-2 for Tappara.
The series now level at 2-2, and after that mammoth contest, the sides are surely in need of some rest, but instead they will go again back in Tampere in less than 24 hours time in game five.
