Steve Kerr accused his Golden State Warriors side of a lack of effort as they slumped to an "embarrassing" 128-95 defeat to the Boston Celtics on Tuesday.

The defending champions slumped to a third defeat in their last four games and their most emphatic at Oracle Arena during Kerr's five-year tenure.

Warriors head coach Kerr was baffled by a lack of desire from the Western Conference leaders.

"Right from the beginning, just the level of completion wasn't where it needed to be," Kerr said. "It was 11 to nothing in about three minutes, four minutes.

"And it looked to me like we were jogging up the floor. You can't play basketball jogging. You got to sprint. Your cuts have to be hard. You got to be going all out. And we did not go all out. And it was embarrassing.

"From the very beginning we were not flying around. We were not giving the sort of effort that it takes to win an NBA game.

"The other stuff I've got to do a better job with. Making sure we're in a position to succeed...it starts with a passion, with an anger, and an intensity. And it wasn't there."

Kevin Durant was not in full agreement with Kerr.

He said: "I thought we move off of joy. Now anger? I disagree with that one. I think all around, top to bottom, coaches, players, we just got to be better."