Things are getting ugly in Brooklyn -- Kevin Durant reportedly drew his line in the sand during a meeting with Nets owner Joe Tsai ... saying the only way he'll stay in New York is if coach Steve Nash and GM Sean Marks get the boot.
33-year-old KD has wanted out of BK since late June ... but as of yet, there hasn't been any progress in granting his wish due to the Nets' asking price to trade their best player.
Now, Shams Charania is reporting the superstar met with Tsai in London over the weekend to reveal his ultimatum ... with sources saying he doesn't have faith in the team's direction.
Durant -- who signed a 4-year, $198 million deal with BK last year -- is singing a different tune than he did in April -- he previously said he felt Nash was doing his job "perfectly," despite all the obstacles the Nets faced so far during his stint at the head of the bench.
"I think he’s done a great job," KD said at the time. "The last two years, he’s been dealt a wild hand. Injuries, trades, disgruntled players, guys in and out of the lineup, stuff that he can’t control."
"I felt like he’s handled it as best he could (and) I think it’s on us as players to make his job easier."
As for Marks, the guy is pretty respected throughout the league and helped get KD and Kyrie Irving -- who also requested a trade this offseason -- to Brooklyn in the first place ... so it sounds like the forward just wants the team to clean house and start over.