You can see in footage of the incident ... Westbrook could not have been more heated as the kernels bounced off his head -- with the D.C. point guard trying HARD to get to the stands to confront the fan.
Russ, though, was eventually calmed down and ushered into the locker room ... but after the game, he said the fan absolutely crossed the line.
"To be blatantly honest, man, this s**t is getting out of hand, especially for me," Westbrook told reporters. "The amount of disrespect, the amount of fans just doing whatever the f**k they want to do, it's just out of pocket, man. It's out of pocket, seriously."
Courtesy of NBA
Russ went on to say if the incident had happened in "any other setting," he insinuated he would've fought the person.
"A guy wouldn't come up on the street and pour popcorn on my head because he knows what would happen," Russ said.
Westbrook then pled with the NBA to "start protecting the players" ... adding, "We'll see what the NBA does."
LeBron James rushed in to defend his pal on Twitter shortly after ... saying he wanted the fan ID'ed and punished ASAP.
By the way WE AS THE PLAYERS wanna see who threw that popcorn on Russ while he was leaving the game tonight with a injury!! There’s cameras all over arenas so there’s no excuse! Cause if the 👟 was on the other 🦶🏾.🎥 #ProtectOurPlayers
"WE AS THE PLAYERS wanna see who threw that popcorn on Russ while he was leaving the game tonight with a injury!!" LeBron wrote. "There’s cameras all over arenas so there’s no excuse! Cause if the [shoe] was on the other [foot]. #ProtectOurPlayers"
So far, no punishment from the NBA has been announced yet ... though high-ranking Wells Fargo Center exec Valerie Camillo did call the incident "classless" and "unacceptable" after the game.
It's unclear, meanwhile, if Russ' ankle injury will keep him out of Game 3 ... the series is set to return to Washington on Saturday with the Sixers up 2-0.