Gennady Golovkin won't guarantee he's gonna kick Canelo Alvarez's ass when they step in the squared circle Saturday night ... 'cause he ain't God.

TMZ Sports talked to GGG and C.A. leading up to their superfight this week in Las Vegas ... and asked each boxer how they visualized themselves winning the bout.

Alvarez said he was preparing for a KO ... while Golovkin's response was interesting.

"Right now it's a 50/50 fight. It's a very dangerous fight. I'm not God."

It's true, he's not God ... he's got a better right hook.