Britney Spears -- lookin' smokin' hot -- was the real MVP of Lakers vs. Warriors on Wednesday ... smooching the night away with 23-year-old BF Sam Asghari courtside at Staples Center.
The Dubs and Lakeshow had an epic OT battle ... but it's pretty obvious Britney and Sam were more into their own 1-on-1 matchup -- while her 2 boys watched the action on the court.
Tons of other huge celebs were in attendance -- including Will Ferrell, Diddy, Jack Nicholson (of course) and proud papa LaVar Ball.
The Lakers lost ... but Lonzo Ball actually knocked down some shots!!