A seething Steve Kerr accused Dillon Brooks of "breaking the code" after an incident that left Gary Payton II with a broken left elbow.
Kerr's Golden State Warriors went down 106-101 to the Memphis Grizzlies, leaving their Western Conference semi-finals series locked at 1-1, in a heated match full of flashpoints.
The Grizzlies' task was made all the more difficult when Brooks was ejected in the first quarter for a nasty-looking strike across the head of Payton II in mid-air.
An X-ray later showed the extent of the damage caused and Payton II is set to undergo an MRI scan on Wednesday.
Kerr acknowledged the physicality of playoff basketball but was fuming with Brooks' play.
"I don't know if it was intentional but it was dirty," Kerr told reporters after the game.
"Playoff basketball is supposed to be physical. Everyone will compete, fight for everything. But there's a code in this league, a code players follow, where you never put a guy's season or career in jeopardy by taking someone out in mid-air and clubbing them across the head and ultimately fracturing Gary's elbow.
"This is a guy who's been toiling the last six years trying to make it in this league, finally found a home, playing his butt off this year – in the playoffs it should be the time of his life and a guy comes in and whacks him across the head in mid-air.
"He broke the code. Dillon Brooks broke the code that's how I see it."
Another heated incident saw Draymond Green raise his middle finger towards the Grizzlies fanbase, who jeered the Warriors star after an elbow to the face left him with a cut to his right eye that had nearly swollen shut by half-time.
Green was unrepentant after the game, saying: "[If] you gonna boo somebody who got elbowed in the eye, face running with blood you should get flipped off.
"So, I'll take the fine, I'll do an appearance and make up the money. But it felt really good to flip 'em off, if you gonna boo someone who got elbowed in the face with blood running down their face, I could have had a concussion or anything.
"If they gonna be that nasty, I can be nasty too. I'm assuming the cheers are because they know I'll get fined. Great, I make $25million a year I should be just fine."
Ja Morant was the hero for the Grizzlies, scoring 47 points – matching his postseason high – despite himself struggling to see out of his left eye having been hit going for a rebound in the third quarter.
The All-Star guard atoned for missing a layup in Game 1 that would have won the Grizzlies the game, a defeat he conceded was at the forefront of his thinking during Tuesday's contest.
"That loss was on my mind a lot, obviously missing that layup late," Morant said.
"But coming into today, I told myself we needed a win, and we were going to get a win. I just took it upon myself to go out there and do that for us."