He transferred to the 82nd Mountain Rifle Regiment of the division at Grozny to become its assistant chief of staff in August 1938.

[1] Then-Captain Dyakonov was sent to the Northwestern Front to fight in the Winter War in late 1939 and appointed commander of the 60th Separate Volunteer Ski Detachment, formed in the 7th Army and designed to bypass Finnish lines on the Gulf of Finland.

Subsequently, Dyakonov led a group of soldiers on a 25-kilometer night march into the rear of the Finnish fortifications defending Tiurinsaari island and attacked elements of the garrison, capturing and holding positions on the island, which enabled the ski detachment to carry out its mission.

For his leadership, Dyakonov received the title Hero of the Soviet Union and was awarded the Order of Lenin on 21 March.

[1] After Operation Barbarossa began on 22 June, Dyakonov left the academy and in September took command of the 27th Separate Cadet Rifle Brigade.

In the spring of 1942, the 31st Rifle Brigade and two ski battalions were placed under the control of the division, expanding its defensive line from 40 to 80 km.

[1] During the Soviet–Japanese War, Dyakonov led the corps in the invasion of South Sakhalin, in which it played a key role, in cooperation with the Northern Pacific Flotilla.

Returning to the Soviet Union, he ended his career as assistant commander-in-chief of the forces of the Moscow Military District for higher educational institutions before retiring on 29 August 1963.