A 5-1 away win in game five made Assat the favourites to take the series, but SaiPa hit back in game six and put the tie back in their favour, winning 3-1 on the road to set up a deciding match in Lappeenranta.
And unlike Assat, they looked to be making full use of home advantage with three unanswered goals in the first 20 minutes. The first came in the ninth minute, as Patrik Siikanen's shot was saved but Jan Bednar in the visiors' goal had no answer to Brian Kramer on the rebound.
A minute later, Pater Tiivola was penalised for high-sticking, and when Otto Kivenmaki's pass from behind the net found Nikkanen, he powered the puck into the net to make full use of the powerplay.
Assat clearly hadn't learned their lesson five minutes later when Feetu Knihti was called for interference, allowing the hosts to enact the same punishment, as this time it was Santari Airola who found Nikkanen to score his second powerplay goal to make it 3-0.
The Aces continued to concede penalties either side of the first break but weren't punished, and got themselves back into the game exactly 20 minutes of play after first conceding, as Roope Talaja reacted well to poke home a rebound and continue his playoff scoring spree.
In the third period, Kramer was denied a second goal following a review, but SaiPa needed only wait three more minutes to re-open the three-goal lead, again on the powerplay following hooking by Knihti.
Antti Kalapudas' shot from the right went wide, and when the puck bounced back off the board, it fell kindly for Nikkanen on the left to slam home his hat-trick goal.
Jan-Mikael Jarvinen's goal a minute later made it 4-2 and ensured the champagne remained on ice, but only for another 11 minutes, as SaiPa closed out the victory to reach the semi-finals once again.
With the top four seeds making the semi-finals, third seeds SaiPa will play KooKoo, and Tappara will face Ilves in a Tampere derby in the best-of-seven series for a place in the Liiga finals. The semi-finals will begin on Thursday 16th April.
Flashscore is the place to follow the Liiga Playoffs.