Alexander Gustafsson to Jon Jones, 'You're Not Going to Survive This'

Alexander Gustafsson says he's "ready for war" -- telling TMZ Sports he guarantees victory over Jon Jones at UFC 232 on Saturday ... "I will dominate every round."

Alex has been cool, calm and confident despite all the drama surrounding the rematch -- and explains he wasn't surprised when Jones tested positive for PEDs again.

"This guy gets confidence by putting sh*t in his body," Alex says ... "He's always been like that, I'm not surprised."

For his part, Jones denies using steroids for the Gustafsson rematch -- and says he only tested positive for an extremely tiny amount of oral Turinabol which was still in his system from a previous incident.