The season came to an end for the Vipers last night as they dropped a 7-2 game in London, and were eliminated in five games by the Nationals.
It was 1-0 London after the first period, and 4-1 heading into the third period.
Isaiah Payne scored twice including the game winner to power the London attack.
Evan Ferguson scored both goals for LaSalle.
Will Tragge made 31 saves for the Vipers while London goalie Zachary Springer made 26 stops.
The Nationals will now wait for the winner of the Leamington/Komoka series which resumes with game five in Leamington tonight, and the Flyers trailing 3-1.