In April 2014, Mikhalkin defeated Mohamed Belkacem by unanimous decision to claim the European light-heavyweight title.

[1] He made three successful defenses of that title, with the last coming against Patrick Bois in March 2016.

[2][3] Prior to his continental title defense against Bois, Mikhalkin tested positive and admitted to taking meldonium, a substance banned by WADA and was stripped by the EBU.

[5] In May 2017, Mikhalkin defeated Thomas Oosthuizen to claim the IBO light-heavyweight title.

[6] On March 3, 2018, Mikhalkin challenged WBO light heavyweight champion Sergey Kovalev for his belt.