[8][9] At the 2016 European Youth Championships in Russia that summer, he won three matches before losing a decision to Englishman Harris Akbar in the semi-finals, taking home a bronze medal.

[10][11] For this achievement he was officially recognized by the president of the Slovak Boxing Federation Peter Bodoki, along with national teammates Filip Meszáros and Dávid Michálek.

[12] Csemez began his campaign at that year's World Youth Championships, also in Russia, with a controversial[13][14] decision victory over medal favorite Brett McGinty.

[25] He was knocked out by Andrej Merzlyakov in the first round of the prestigious Chemistry Cup in Germany in June 2018,[26] then lost by referee stoppage to Nicoleto Grdovič at an international tournament in Slovakia in what was his light heavyweight debut.

[27] After this rough return, he then won a gold medal in the middleweight event at the European Union Championships in November, winning all four bouts by unanimous decision.

[30] However a few weeks later he won a gold medal at the second Euro Cup in Bijeljina, Bosnia and Herzegovina in his return to light heavyweight, and was given the best boxer award.

He defeated Ryszard Lewicki in the opening round and was scheduled to face Miguel Cuadrado of Spain next, but the competition was postponed after three days due to the COVID-19 pandemic.