Doc Rivers said the LA Clippers are "very emotionally weak" and are not the elite defensive team they are supposed to be right now.

Rivers was upset with his team's mental toughness and execution after Luka Doncic capped an incredible Game 4 performance with a 27-foot step-back 3-pointer at the buzzer in overtime to lift the Dallas Mavericks to a 135-133 victory over the stunned Clippers.

With the series tied 2-2 and the heavily favored Clippers in a dogfight with the Mavericks, Rivers said that he saw the Clippers "cave in" when Dallas made a huge run and that he has to do a better job of getting the second-seeded team in the West right for a crucial Game 5.

"Honestly, I thought we were very emotionally weak tonight," Rivers said. "... If I knew [why], I would be Sigmund Freud. But at the end of the day, we're up 20, and we're getting technical fouls. Things like that give the team juice. Throughout -- and I've been saying this for three games now -- we're so much better than what we're playing. But honestly, give Dallas credit. ... They're minus [Kristaps] Porzingis. But they just kept playing. They played together. They moved the ball.

"And you can see the difference in spirit. Like, they make a run, and everybody's excited. You know, they make a run on us, and we cave in. So that's on all of us. Me, too. I've got to get our guys right."

After Porzingis was a late scratch because of a knee issue, the Mavericks fell behind 54-33 with 7:39 left in the second quarter. Then they stormed back, outscoring the Clippers 51-21 to take an 84-75 lead with 3:46 remaining in the third quarter.

Doncic had 16 points and six assists during the game-turning Dallas run and torched the Clippers' defense with 43 points, 17 rebounds and 13 assists as his team evened the best-of-seven series.

"We're fine that way," Rivers said of what the loss does to the Clippers mentally. "The series is 2-2. You can make a case it should be 3-1. ... But at the end of the day, the series is 2-2.

"We gotta play better. Listen, defensively, without Porzingis, they scored 135 points, and we're supposed to be an elite defensive team. Right now we're not. ... They just stared us in the face and beating us off the dribble."

On the final play of the game, Kawhi Leonard started on Doncic until he switched off of the Dallas star on a screen, leaving Reggie Jackson to defend Doncic on the buzzer-beater.

"Yeah, you always switch everything at the end of the clock," Rivers said of how the Clippers defended that play. "But you're supposed to switch to a denial. And we didn't.

"We switched and allowed their best player to catch the ball with three seconds left."

Leonard (32 points, nine rebounds) and Lou Williams (36 points) kept the Clippers in the game and helped the team erase a 119-111 deficit with less than two minutes remaining in regulation.

But Paul George continues to be mired in a bad slump, shooting 3-for-14 overall, including missing six of seven from behind the 3-point arc to finish with nine points and eight rebounds. George said he believes that if he had made more shots, the series would not be tied. In his past three games, George is shooting 10-for-47 overall and 4-for-25 from 3-point range.

"It's just tough for me right now," George said. "It's hard to say because I am getting the looks, the shots, the floor is open, and the defenders aren't great, but I'm just having a hard time finding the ball through right now."

"Give them credit," George later added. "They're playing well, they're defending, they're shooting the ball, Luka is playing phenomenal -- you gotta give credit where credit is due. But to be honest, in hindsight, if I shoot the ball better, this series would be a lot different."

Leonard reiterated his confidence in George and that the shooting guard will turn things around.

"His time is coming," Leonard said. "He had some easy looks tonight. Everybody did, but it's not his fault."

George said "I am not sure" when asked about Rivers' saying that the Clippers were "emotionally weak" in Game 4.

Leonard said there is plenty of series left for the Clippers to find their defense and edge. Rivers said he hopes the team listens to Leonard and the message he's trying to deliver for Game 5.

"I think just the two guys that are doing the most positive talk were Lou and Kawhi," Rivers said. "... But everybody has got to follow that, too. And sometimes you want to hear it, and sometimes you get inside your head and you don't hear it. I thought tonight was a night that a lot of messages were not delivered, including mine. So that is something that as a coach I always take on myself."

"I don't think we've been a great individual defensive team," Rivers later added. "I think we've been passive. ... Give them credit. They're so much the more physical and the more aggressive team. It's not even close."