Assat got the better of Hameenlinna in a closely-fought game one yesterday, but this match was even tighter - as Assat needed overtime to secure a 2-1 victory.
At the end of an ill-disciplined first period that saw Petteri Nikkila and Nestor Noiva heavily penalised for fighting, the home side scored the opener two minutes before the break through Eetu Tuulola.
There were no goals in the middle period, but as the penalty count rose, it was inevitable that the Assat equaliser would be scored on the powerplay.
Dylan Fabre found the back of the net to level the scores with under 11 minutes remaining.
Assat thought they had won it in the final 10 minutes, only for Eemil Erholtz's goal to be disallowed following a video review.
However, the win was in the bag after just one minute and five seconds of overtime, as Roope Talaja and Miro combined to set up Kasperi Ojantakanen for the game-winning goal.
Tappara could not find a way through the Kiekko-Espoo defence in Tuesday's meeting, but they more than made up for that with an emphatic 6-1 win on home ice.
Mario Kempe broke the deadlock 11 minutes into the game and when he scored his second, nearing the midpoint in the match, that made the score 4-0 thanks to Benjamin Rautiainen's and Petteri Puhakka's goals earlier in the second period.
Two minutes into the third, Otto Rauhala made it five, and though Aleksi Laakso got K-Espoo on the board, the last laugh went to the "Battle Axe", when Puhakka scored his second of the night.
The team in the postseason with the worst record from the regular season are the first to open up a two-game lead, as TPS Turku beat SaiPa 6-2 at home, fresh from their 2-1 win yesterday.
SaiPa seemed ready to enact revenge two minutes in when Mark Pysyk gave them the lead, but it took less than 90 seconds for Eetu Pakkila to get TPS on level terms.
The second period belonged to the home side - Lukas Wernblom, Leevi Teissala and Casimir Jurgens all got in on the act to put the Turku side 4-1 to the good.
Ville Petman reduced the deficit, only for Topias Haapanen to make it 5-2 by the end of the second.
Late on, Pakkila grabbed his second of the match with an empty-netter to round off the big win.
The away side took the spoils for the second night running in the match-up between Vaasan Sport vs KooKoo, as the Kuovola side won 3-0 in Vaasa.
Teemu Engberg gave KooKoo the lead with three minutes left in the first period, before the lead was doubled by Seth Barton, 13 minutes into period two.
Pulling the goaltender came back to bit Sport late on, as Saku Salmela found the empty net, meaning KooKoo won all three periods 1-0 in a professional performance.
Game three of each First Round tie takes place on Friday, in which, Assat and TPS have the chance to secure a series victory and book their places in the Quarter-finals.