Joel Embiid and Marcus Smart's brush-up during the Boston Celtics' Opening Night win over the Philadelphia 76ers stole headlines. However, this wasn't the first time Embiid and Smart went back-and-forth. Sixers' staff writer Sean Barnard reports that Embiid's first ever Instagram post was him dunking over Smart. And his caption certainly threw shade Smart's way.

“Not very SMART to jump on that one,” Joel Embiid wrote.

Popular YouTube channel “Secret Base” even posted a video detailing Marcus Smart and Joel Embiid's beef history in 2021. They took an in-depth look at the two's relationship and found that they have taken issue with one another since college. Their beef was not previously widely-known, but it certainly is now following Tuesday's incident.

Smart accused Embiid of trying to break his arm and said he “could have cracked his head open.”

“Went for a rebound,” Smart said. “Basketball play, went for a steal. My arm’s still stuck in there and he tries to break it. And I’m the only one who gets a tech. Everybody saw it. If I did that, I’m probably ejected, suspended. Three games, four games, fines. … Defending DPOY and that’s how he gets treated? It’s tough. I could have cracked his head open, but I didn’t. That’s the maturity we have.”

Joel Embiid shared his take on what occurred as well.

“They had called a foul and I walked away, next thing I know, my foot is getting caught up, and I slipped,” Embiid said. “Next thing, Jaylen was on top of me and I don’t know. Basketball. Emotions, first game of the season, rivalry, Boston-Philly, a lot of intensity. It’s all good.”

The Sixers-Celtics next matchup will be must-watch TV without question.