The four-goal loss in Vantaa means Finland must win Sunday's (22nd March) second leg in Podgorica by at least four goals to stand any chance of reaching a major tournament for the first time since the 1958 World Championship.
It's the second damaging home loss to Montenegro in a matter of months for the Finns, who were beaten by five goals last May, a defeat that all but ended their ambitions of reaching this year's European Championship.
Much of the damage was done this evening in the first half, as the visitors never led for the entire 30 minutes after scoring the opening goal.
Montenegro quickly built up a 6-2 lead, which soon became a five-goal advantage, but Finland rallied late on, as Fredrik von Troil and Kalle Kankaanpaa notched the final two goals of the half to make the score 16-13 at the break.
Those goals spurred Finland on at the start of the second half, as two from Max Granlund and another from Benjamin Helander got the home side level at 16-16. The teams then traded goals six times, before Montenegro took control again at 25-23 with 15 minutes to play.
Finland came back again and took the lead for the one and only time through Kankaanpaa at 26-25 three minutes later, but that only served to usher in Montenegro's best spell of the game - a 5-0 run as the match entered its last 10 minutes to seal victory.
The Adriatic side eventually took a 36-32 win that maintains their hopes of going to the World Championship for the third time as an independent nation, leaving Finland with the need to pull off a surprise in the return leg.
Luka Radovic top-scored in the match with nine goals, as Granlund's seven was the best offering from a Finnish player.
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