KalPa secured a first Finals appearance since 2017 with a thrilling 5-4 win at home to Ilves.
The visitors, needing a first away win of the series to stay alive, began well and opened the scoring inside two minutes, when Toni Utunen exploited a gap through a crowded attacking zone to fire past Dominik Pavlat.
But the lead lasted just 76 seconds, thanks to Patrick Curry's slap shot being deflected into the net by Jere Karjalainen, and that's how things stayed until the 16th minute, when Curry turned from provider to scorer.
The Lynx coughed up the puck in their defensive zone, allowing Jesper Mattila to play it in front of the net for Curry to bury with a one-timer.
30 seconds into period two, there looked to be only one winner, as KalPa went 3-1 ahead. Again, the home side forced a turnover in their attacking area, and Matyas Kantner was on hand to force the puck in from in front of the net.
But the Tampere side were not done - closing the gap back to one three-and-a-half minutes on, using body parts to full effect. Arttu Pelli controlled an attempted clearance with his hand, before playing the puck to Joonas Nattinen, who turned it in with an outstretched foot.
However, momentum swung back KalPa's way, when Curry used the space afforded him on a powerplay to score his second of the evening.
In the third period, Ilves not only reduced the lead again, but found the crucial equaliser.
Simon Johansson found the tightest of gaps between Stefanos Lekkas and the pipe to make it 4-3, then on a powerplay, the visitors did well to keep an attack alive before working the puck to Carl Klinberg, who put it beyond the goaltender's reach.
Despite forcing the extra time, Ilves were unable to force an extra match - conceding a powerplay midway through overtime, the Lynx could not stop Juuso Maenpaa driving forward and beating Pavlat all ends up, sparking wild scenes at Olvi Areena.
Joining the Kuopio side in the Finals will be SaiPa, who had never finished in the top three of the Liiga before, but will be guaranteed at least a silver medal after winning 2-1 in overtime against Lukko.
Like Ilves, regular season winners Lukko needed to win game six on the road to keep the series alive, but after a goalless first period, things began to go against them when Antti Saarela's goal was disallowed early in the second.
Adding insult to injury was Santari Airola, who broke the deadlock midway through the match, firing into the top corner from wide out on the right.
But the Rauma men rallied, levelling the scores late in the same period when Henri Ikonen was in the right place to score on the rebound after Kari Piiroinen kept out Steven Jandric's initial effort.
Piiroinen made eight saves in the third period to Joni Ortio's six, as the tension in Lappeenranta grew and grew as overtime closed in.
That tension was cut just 59 seconds into the extra period when Airola, the coolest man in Lappeenrannan Jaahalli, picked the loose puck up just inside the blue line, danced his way past three Lukko defenders, and steered the puck past Ortio to score an outstanding winning goal.
The SaiPa players and fans celebrated a maiden Liiga Finals appearance, the first match of which will be in Kuopio on April 25th.