Oscar De La Hoya says battling cocaine addiction is the toughest fight there is -- but he's confident heavyweight champ Tyson Fury can beat his blow problem ... as long as he gets help.
Of course, Fury was yanked out of his upcoming fight with Wladimir Klitschko after testing positive for cocaine -- and later admitted, "I've done lots of cocaine. Lots of it."
Since Oscar has been so open about his own struggles with coke -- and since he's still a major player in the boxing world -- we asked if he thought the drug tests will end Tyson's career for good.
"No," Oscar said ... "I think he's going to come back stronger than ever."
"He just has to go get the help and stick with it. It'll be the toughest fight of his life but I think he can do it. He's a fighter."
"I believe in him."