Boxing superstar Sergey Kovalev has been charged with felony assault for allegedly punching a woman in the face back in June -- but he claims he's not guilty ... TMZ Sports has learned.
Here's what we know ... the Russian fighter was arrested in Big Bear, CA on June 9 after a woman told police the former light heavyweight champion socked her in the face, causing serious injuries.
Sources connected to the case tell us ... the woman is claiming Kovalev had hit on her at a party earlier in the evening but rejected his advances.