CLEVELAND — Leon Powe has seen the Boston Celtics at their best. They aren’t there anymore.

After coming off the bench and helping the Cleveland Cavaliers put away the Celtics 104-93 on Sunday, Powe, who won an NBA title with Boston in 2008, took a moment to reflect on his former team, a squad showing signs of age and perhaps vulnerability.

“Looking at the defense from the championship year, when we won it, it doesn’t look the same,” Powe said. “It looks like the rotation is slower and they ain’t getting to the shooters and closing out like they did before. I don’t know if it’s effort or maybe they’re a little older. But they’ve been old.”

The Celtics looked it.

LeBron James scored 24 of his 30 points in the second half and the Cavs wore down the Celtics for their second decisive win over one of the East’s premier teams in less than a month.

The Cavaliers were closer to full strength with the return of forward Antawn Jamison, who had 15 points and 12 rebounds after missing one game with a sore knee. Anderson Varejao had 17 points, 10 boards and drove the Celtics crazy with his nonstop hustle.

“I thought one guy completely dominated the game and that was Varejao,” Celtics Coach Doc Rivers said. “Loose balls, activity, getting under our skin, he’s doing what he should do. That was very frustrating. He was so active. He moved his feet and we didn’t.”

Last month, the Cavs beat the Celtics by 20 in Boston. In that game, Cleveland center Shaquille O’Neal sustained a serious thumb injury and is expected to miss the remainder of the season.

The Cavs don’t appear to be missing him right now.

Ray Allen scored 20, while Paul Pierce and Kevin Garnett, who was in foul trouble for most of the game, had 18 apiece for the Celtics.

Boston’s Big Three was no match for James.

James added eight rebounds, seven assists and three blocks in another MVP-type performance. He also shook off being accidentally poked in the left eye in the third quarter by Garnett.

“I’ve got kind of a headache right now,” said James. “I was lucky to be able to finish the game. It stayed blurry for about 15 minutes. It wore off close to the end of the fourth.”

Leading by eight after three, the Cavs scored the first nine points in the fourth. Cleveland’s defense, which usually gets tougher in the final 12 minutes, forced the Celtics to take bad shots and Boston missed its first eight shots in the fourth. The Cavs have held the Celtics to 24 percent shooting (10 of 41) in the past two fourth quarters.

“Defensively, we were awesome in the fourth,” James said. “Fourth-quarter time is our staple and that’s when we turn up the aggression. That’s exactly what we did.”

Rajon Rondo had 16 points, eight rebounds and six assists for the Celtics.