Rajon Rondo played his best game of the series Monday.

Journal / Glenn Osmundson

WALTHAM, Mass. — He played almost 34 minutes, sank 7 of his 14 shots for 15 points, picked off three rebounds, passed for four assists, made two steals and turned the ball over just three times.

The Celtics lost Game Four of their second-round playoff series Monday night, but guard Rajon Rondo played well enough to earn kudos from his coach.

“I thought Rondo was terrific,” coach Doc Rivers said.

Like the Celtics, Rondo has been up and down in this series, which is tied 2-2. He scored 15 points in the first game but only 7, all on free throws, in the second. He scored seven again in the third game but shared the scoring lead with Ray Allen in the fourth.

“His decisions were right. I got on him for one shot, and that was the three that he settled for, where he had made one and he actually was looking for a three instead of a drive. Other than that, I thought that was his best game in this series.”

Rivers appreciated that his second-year guard “was aggressive, but aggressive to make plays, not aggressive for him to score. That’s what we talked about. He’s one of those guys that could have easily thought, ‘I’ve got to get myself going.’ I thought he took the right approach. He almost took the LeBron [James] approach (of) ‘I’ve got to make plays, whether that’s scoring or for my team.’ I thought Rajon was terrific.”

Hitting a couple of jump shots boosted Rondo’s confidence.

“It doesn’t hurt,” Rivers said. “He’s going to keep getting those, and we understand that. All we talked about between the two games is you have to take them. I thought the first game in Cleveland he had those same shots and decided to try to create and put the ball on the floor. You don’t have to take them all, but you have to take a couple of them, and I thought he did. You know, he works on that shot every day, and he makes it. You got to believe that even if you miss the first one, you got to take it, and I thought he did a good job of that.”

A veteran presence

Backup forward P.J. Brown played almost 23 minutes Monday night, his longest stint of these playoffs by far. He made all four of his shots for eight points, grabbed six rebounds and blocked two shots.

But the 6-foot-11 forward/center shouldn’t expect another marathon appearance any time soon.

“P.J.’s terrific, but he’s going to stay in the same rotation he’s been in,” Rivers said.

The coach added that Brown, a 15-year veteran, is the biggest surprise of the playoffs.

“He has started to make that jump shot, which is huge, and his length on the floor, with him and Kevin, is huge for us defensively. I didn’t know he could give us this much. He’s actually improving as the playoffs are going on.”

Good to be king

The Cavs’ James isn’t having a great shooting series — he is making only 25 percent of his shots — but he is torturing the Celtics with his all-around play.

“He’s really hurting us more than people give him credit for. He’s making great plays. He really is,” Rivers said. “We’re getting in his face, and he has to take tough shots, but we’re allowing him to make more plays than we should be, and we have to do a better job at it.”

He cited a couple of passes James made to Daniel Gibson in the fourth quarter for key baskets.

“Give LeBron credit. He found the guy, and he made the shot,” Rivers said.