Poland's Wlodarczyk was sent to the canvas in the third round as he took a pounding from the Russian over the first five rounds at the Dynamo Palace of Sports.
Chakhkiev, unbeaten in professional bouts heading into this encounter, appeared to be pummelling his way to victory until he was suddenly floored in the sixth by a left hook.
That changed the complex of the bout and Wlodarczyk seized his chance, knocking Chakhkiev down again in the seventh before downing him twice more in the eighth. The second time he hit the canvas, referee Daniel Van de Wiele stepped in and called an end to the fight.
Wlodarczyk's record improves to 48-2-1 (34 KO), while Chakhkiev slips to 16-1 (12 KO).
- Sports & Recreation
- Dynamo Palace of Sports