There are some things you can only learn in college, and Justin Bieber is discovering that the hard way.
Bieber attended a pool party at the Marquee Nightclub & Dayclub inside of The Cosmopolitan in Las Vegas on Saturday, where he took part in the art of shotgunning a beer. Most popular at fraternities at colleges and universities, it's a drinking game where you poke a hole in a can of beer, cover the hole with your mouth, pop the tab and consume your beverage as fast as possible to beat your opponent(s).
WATCH: Justin Bieber Reveals Why He’s Single
Corona Extra in hand, the 21-year-old went up against Sam Shahidi, co-founder of the anti-bullying app, Shots, which Bieber invested in.
Even though he clearly lost the drinking race, the "What Do You Mean?" singer was a good sport about it. "I lost but I didn’t go to college," he wrote of the failed attempt, which he posted on Instagram.
Bieber was in Vegas to cheer on his friend, undefeated boxer Floyd Mayweather, in the figher's bout against Andre Berto at the MGM Grand Garden Arena on Saturday night.
"Like always, I'm supporting @FloydMayweather tonight live on PPV," he captioned a photo of the two.
NEWS: Justin Bieber Scores First No.1 Hit
It was a memorable fight for Mayweather. By defeating Berto in a unanimous decision win, the 38-year-old matched the 49-0 career record of legendary boxer Rocky Marciano. "My career's over. It's official," Mayweather said. "You've got to know when to hang it up."
As usual, Bieber congratulated his friend's win with a photo on Instagram, which he later followed up with an artistic solo shot inside the arena.