President Trump to STL Blues Player, 'Think I Could Take Him in a Fight!?'

The St. Louis Blues celebrated their Stanley Cup title at the White House on Tuesday ... with President Trump crackin' jokes and picking hypothetical fights with the players!!!

The champs were honored at 1600 Penn. for beating the Boston Bruins in Game 7 to win it all last season ... and one player, Alexander Steen, got POTUS' attention (for obvious reasons).

"Look at that guy, look at the mouth on that guy," Trump told the crowd. "Come here a minute, come here."

"You think he's taken a few hits? You think I could take him in a fight?! I don't know."

There was more funny business ... with the stars of the team, like Jaden Schwartz, issuing a golf challenge to POTUS ... and Trump calling out rookie Jordan Binnington for giving up ONE goal in Game 7.

"He stopped 32 of 33 [shots], so why didn't you stop the other one, Jordan? You coulda made the game a lot easier!"