Semelka claimed his first aerial victory on 22 June 1941, the first day of Operation Barbarossa, the German invasion of the Soviet Union.

Gruppe of JG 52, without a period of replenishment in Germany, was ordered to airfields close to the German-Soviet demarcation line.

Fliegerkorps commanded by Generaloberst Wolfram Freiherr von Richthofen which supported the northern wing of Army Group Centre.

[4] The Gruppe supported the advancing 9th Army and 3rd Panzer Group in their attack on the border fortifications east and southeast of Suwałki.

[6][Note 1] On 25 June, the Gruppe moved to an airfield at Varėna in Lithuania which had previously been occupied by the Soviet Air Forces (VVS—Voyenno-Vozdushnye Sily).

[11] Here, the Gruppe supported the fighting south of Lake Ilmen, and the German attacks on Shlisselburg, Leningrad and the Soviet fleet at Kronstadt.

[12] Operating from Soltsy, Semelka claimed an I-17 fighter, an early war designation for the Mikoyan-Gurevich MiG-1, and a Vultee V-11 ground attack aircraft, probably referring to the Ilyushin Il-2, shot down on 14 August.

Gruppe was ordered to Lyuban, approximately 70 kilometers (43 miles) to Leningrad and located on the road to Moscow.

[15] The Gruppe stayed at Lyuban until 30 September, flying missions to Shlisselburg, Leningrad and Mga.

[17] On 2 October, German forces launched Operation Typhoon, the failed strategic offensive to capture Moscow.

[18] While stationed at Kalinin, the Gruppe was so close to the front line that their airbases were shelled by Russian artillery, and ground crew had to defend against enemy attacks.

On 27 November, he claimed his 17th in total and last aerial victory of 1941, a BB-22 light bomber/reconnaissance aircraft referring to the Yakovlev Yak-2.

Gruppe was withdrawn from the Eastern Front and sent to Jesau near Königsberg for a period of recuperation and replenishment, arriving on 24 January 1942.

Gruppe received orders to move to Pilsen, present-day Plzeň in the Czech Republic, for relocation to the Eastern Front.

[25] The Gruppe then moved to Wien-Schwechat on 24 April before flying to Zürichtal, present-day Solote Pole, a village near the urban settlement Kirovske in the Crimea.

Gruppe participated in Operation Trappenjagd, a German counterattack during the Battle of the Kerch Peninsula, launched on 8 May.

[24] On 12 May, Semelka crashed his Bf 109 F-4/R1 (Werknummer 13057—factory number) near Marfivka, a village located approximately 20 kilometers (12 miles) east of Chelyadinove.

Gruppe relocated to Artyomovsk, present-day Bakhmut where JG 52 supported the German forces fighting in the Second Battle of Kharkov.

The main German objectives in that combat area were, breakthrough to the upper Don and capture of Voronezh.

[32] On 28 June, the Wehrmacht initiated Fall Blau (Case Blue), the 1942 strategic summer offensive in southern Russia.

Gruppe moved to an airfield named Nowy Cholan, approximately 200 kilometers (120 miles) northeast of Rostov-on-Don.

[41] On 18 August he shot down five fighters making him an "ace-in-a-day" for the second time, in two missions over the Black Sea coast near Novorossiysk.

It is possible he was shot down and killed by return fire from Pe-2 bombers of 86 BAP (Bombardirovochnyy Aviatsionyy Polk—Bomber Aviation Regiment).

[43][44] Alternatively, Semelka may have been shot down in his Bf 109 G-2 (Werknummer 13558) by a Douglas A-20 Havoc bomber north of Srednyaya Akhtuba.