In June 1941 Filimonov served with the 147 IAP. This unit was based in the far north end of the Karelian Front, defending the harbours of Murmansk and Arkhangelsk, equipped with Polikarpov I-153s.

On 25 June he claimed a shared Ju88 with his wingleader Starshiy Leytenant Leonid Ivanov over Kandalaksha.

Filimonov ended the war with 1 shared biplane victory, this one being claimed while flying the I-153.

Claims:

Kill no.	Date	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1941
	25/06/41	½	Ju88	Shared destroyed	I-153		Kandalaksha	147 IAP

Biplane victories: 1 shared destroyed.
TOTAL: 1 shared destroyed.

Sources:
Geroi lenigradskogo neba - 1984 Lenizdat kindly provided by Vladislav Arhipov
Stalin's Falcons - Tomas Polak and Christhoper Shores, 1999 Grub Street, London, ISBN 1-902304-01-2