... but the whole thing makes ya wonder -- how would Goldberg have fared in the Octagon?!

Probably pretty well.

"If you know anything about my background when it comes to MMA, I had one of largest MMA gyms in the country back in the late '90s. That was a dream of mine."

Goldberg says he trained alongside UFC legends like Randy Couture and Mark Coleman when they were in their prime.

But, let's get to the point ... how would he do in a real MMA fight?

"I think my stand up skills would have played well, no question," Goldberg tells TMZ Sports ... "because a lot of people have no idea as to what I've done in the past."

"But, I'd be lacking in the ground game, there's no doubt -- and the problem with a guy like myself is I'd end up hurting myself more so than getting hurt by the other person. I'll break a hand on someone's face! I'll blow my shoulder out trying to choke somebody! At the end of the day, I'm my own worst enemy!"

"So the longwinded answer is absolutely I would have loved to have done it if the opportunity was such that it was comparable, if not more advantageous, in the world of professional wrestling. But, at the time, it was a no-brainer for me."

Don't feel too bad for Goldberg, he's had an unreal run as a pro wrestler and is set to face Drew McIntyre in a Championship bout at the Royal Rumble on Sunday.

Goldberg -- who famously trained with UFC star Dustin Poirier back in 2015 -- says the plan is to do to McIntyre what Poirier did to Conor McGregor!

The WWE legend also raved about Poirier -- and told us why he's still inspired by the UFC star ... who's one of the most humble and hardworking athletes he knows.

"He's from Lafayette Louisiana, it's a great story and I just hope people understand -- I've said many times about a few people, his talents are at the top of the game but they pale in comparison to what is actually inside his heart. He's a great person."