Dave Portnoy Wins $2.7 Million Betting On UConn National Championship

There might not have been anyone happier to see UConn win on Monday night than Dave Portnoy ... 'cause the Barstool Sports founder made over TWO MILLION DOLLARS betting on the Huskies to take home the national championship.

The 47-year-old put down $600K on Dan Hurley's squad to win the NCAA tourney just before March Madness kicked off last month ... and at the time, he said he was a bit worried -- as Connecticut was nearly everyone's pick to win it all.

But as UConn boat raced Purdue in the title game in Glendale, AZ ... those nerves melted away -- and his wallet got a whole lot fatter.

Portnoy revealed he netted a total of $2.7 MILLION off the wager ... and afterward, he gloated about it all on his X page.

"The greatest bet of my life," he said. "Thank you #uconn. Destroyed everybody and everything in their path. They'd win the tournament 100 out of 100 times. The biggest win of my life by a mile."

Portnoy didn't even really have to sweat it ... as UConn led pretty much wire-to-write en route to a 75-60 victory.

The Huskies held Zach Edey to 37 points on 25 shots ... and limited the Boilermakers to just seven total 3-point attempts. They won every game of their tournament run by double-digits.