Having held their nerve to win 22-21 in Vantaa on Thursday, the Finns new they must take something from the return fixture in Hlohovec to stand a realistic chance of finishing in the top two.
The first half in Slovakia was almost a copy of the first 30 minutes of Thursday's match, with neither side able to open up a lead of more than two goals.
This time, though, it was the home side who held the advantage at the break, 15-14.
However, the match turned in the first eight minutes of the second half, in which Finland scored five unanswered goals - three of which came courtesy of Benjamin Helander - to lead 19-15.
Desperate to keep their qualification hopes alive, Slovakia worked their way back into the match and reduced the deficit to one at 23-22.
It looked to be job done for Finland at 26-23 with three minutes left, only for their attack to completely falter at the death, as it had done in Vantaa.
The home side reduced the gap to one again as Marco Antl hit 10 goals in the game, but Finland's defence held firm in the last minute to win 26-25.
The win takes Finland to four points in the group, one point behind Montenegro, who drew 29-29 with leaders Hungary in Tatabanya.
With Hungary close to sealing their place at Euro 2026 and Slovakia now eliminated, the group could be decided by Finland's home match with Montenegro next, on May 8th.
Even with a win, Ola Lindgren's side will not be able to take things easy in their final match, away to Hungary on May 11th, as Montenegro welcome Slovakia.
EHF Euro 2026 will take place in January and February next year, hosted by Norway, Sweden and Denmark.
