Mateusz Masternak has six losses against six opponents on his boxing record. For a list of Masternak's best fights, refer to "Best fights of Mateusz Masternak".
On December 10, 2023 Mateusz Masternak fought Chris Billam-Smith in a cruiserweight world-title fight for Billam-Smith's WBO title. Masternak was 36 years old and with a record of 47-6 (31), and Billam-Smith was 33 years old and with a record of 18-1 (12). Masternak lost the fight via 8th-round retirement.
On October 20, 2018 Mateusz Masternak faced off against Yuniel Dorticos at age 31. He was coming in with a record of 41-5 (28), and Dorticos was 32 years old and with a record of 22-1 (21). Masternak lost the fight via 12-round unanimous decision.
On December 12, 2015 Mateusz Masternak faced off against Tony Bellew in a cruiserweight bout at age 28. He was coming in with a record of 36-4 (26), and Bellew was 33 years old and with a record of 25-2-1 (16). Masternak lost the fight via 12-round unanimous decision.
On June 6, 2015 Mateusz Masternak faced off against Johnny Muller at age 28. He was coming in with a record of 35-3 (25). Masternak lost the fight via 10-round split decision.
On June 21, 2014 Mateusz Masternak fought Youri Kayembre Kalenga in a cruiserweight world-title fight for Kalenga's WBA title. Masternak was 27 years old and with a record of 32-2 (23). Masternak lost the fight via 12-round split decision.
On October 5, 2013 Mateusz Masternak faced off against Grigory Drozd in a cruiserweight bout at age 26. He was coming in with a record of 30-1 (22). Masternak lost the fight via 11th-round TKO.
