Finland exploded from beyond the arc with 13 three-pointers and ruled the rebounding department with 55 boards to hold off Gilas.
Previously, Gilas bowed to Estonia, 81-71.
Thompson played against Finland after recovering from back spasm and naturalized player Justin Brownlee was no longer bothered by cramps.
They aided the nationals to stay within striking distance of Finland most of the game. But it was not enough to topple the Finnish.