[2] Since 1943 he was a member of the Communist Party of the Soviet Union In the summer of 1944, the division commander, Major General Andrei Stuchenko, gave the Tretyak the combat mission of leading an advance detachment together with a tank battalion.

Following the order, the tank crews and infantrymen drove into the German rear in vehicles and secretly reached the Velikaya River along forest roads.

A ford was found, along which the detachment successfully crossed and, with a final night dash, reached the outskirts of the city of Opochka.

The appearance of tanks with troops on their armour was a complete surprise for the German garrison, and panic arose.

With daring actions, the soldiers captured the city, inflicting heavy losses on the enemy.

From January 1960 he served as Chief of Staff and First Deputy Commander of the 3rd Combined Arms Army in the Group of Soviet Forces in Germany.

In 1967-1976 he served as Commander of the troops of the Belarusian Military District, in 1976 he refused the appointment of his deputy for logistics proposed by the Minister of Defense.

On September 1, 1983, he received an order from the Chief of the Main Operations Directorate and First Deputy Chief of the General Staff of the Soviet Armed Forces Valentin Varennikov to destroy a passenger Boeing 747 plane of the South Korean airline Korean Air, which violated Soviet airspace, and carried it out, giving orders to his subordinates to destroy the aircraft.