Darkish,
If you hold a high G manuver too long the blackout seems to become unconciousness. I've had it happen to me at least once. I was in a Spit IX being attacked by three P-51Ds and had altitude to burn, so I pulled into an insane downward spiral that there was no chance the P-51Ds could match. I was blacked out for a long time, then when I let up on the stick the blackout didn't recede. I tried for a bit to get vision back, then I hit the ground.
A blackout should not take away the control of the aircraft as a blackout doesn't indicate anything more than your eyes not getting enough blood to work. You are still fully concious in a blackout.
Hold it too long though and it can become a loss of conciousness and you do lose control of the aircraft with that.