Actually not - towards the end of WWII the Russians* launched a counteroffensive against Finnish (and some Nazi) forces around Leningrad - they greatly outnumbered the Finns and pushed them well back into Finland.
The Winter War of 1939-1940 was another story (for awhile anyway) - the Russian forces greatly outnumbered the Finnish forces and they thoroughly thrashed the Russians in the harsh winter. The Russians re-organized, resupplied and changed their strategy so they could take advantage of their numerical superiority. The Finns were then forced to surrender.
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*In August of 1941 Stalin asked Roosevelt to arrange restoration of peaceful relations with Finland and offered to return territories to Finland. In what was a serious mistake (in hindsight) the Finns refused - driven by hatred of the Soviets and at the time it seemed that the Germans would win.