Mike Eruzione Gives Justin Gaethje Advice Before UFC's Freedom 250

Justin Gaethje's a big underdog against Ilia Topuria at The White House ... so, what does the MMA star have to do to pull off the big upset?? Team USA hockey legend Mike Eruzione is sharing a few words of wisdom.

It all started when TMZ Sports talked to 37-year-old Gaethje last week, and he told us he was gunning to bring "Miracle on Ice" energy to his Freedom 250 fight against Topuria, who is a substantial betting favorite.

As UFC fans will know ... Justin's from 'Merica, while Ilia lives and fights out of Spain.

Eruzione knows a little bit about facing seemingly insurmountable odds as an American athlete ... and he's offering advice to Gaethje.

"Obviously, I know a little bit about [Justin]. He's a mean man. He's a tough, tough guy," Mike told us.

The hockey icon continued, "When I hear that kind of stuff, I just tell people to embrace the challenge. That's what we did. We weren't afraid of it. We were excited about it. And I think that's the way you have to be. As I tell people all the time, if you think you're going to lose, you probably will. So despite the fact that nobody thought we could win, let's play the game and let's find out."

The 1980 Olympic gold medalist added ... "My advice to him is go out and fight. See what happens. But embrace the challenge. Embrace the opportunity. Cherish it. Enjoy it. Get pissed off."

Of course, Mike's hockey team achieved the unthinkable in Lake Placid ... with head coach Herb Brooks leading a group of amateur and collegiate players, defeating the Soviet Union, widely considered one of, if not the greatest team ever assembled, 4-3, and going on to win the gold medal.

Justin may not be that level of underdog, but he's a serious longshot ... and the captain of the legendary 1980 squad thinks he can use that as fuel behind his hits.