BOSTON - Who does the best center in the NBA, Orlando's Dwight Howard, hate facing more than anyone else?

Boston center Kendrick Perkins, who held Howard to just 13.1 points per game in the Eastern Conference semifinals last season.

Howard says that nobody guards him as well as Perkins does. He credits Boston assistant coach Clifford Ray for making Perkins into one of the best defensive centers in the game.

"He's very smart, and I worked with Cliff from the time I got into the league until the time he left to come to Boston. He was a big help for me and he's really helped Kendrick's game. I'm real happy to see the progress that Kendrick has made, not just defensively, but offensively, since he's came into the league.

"We worked out together and when we came out, we he got drafted, and to see him now, I'm just happy to see that he's grown [under] Clifford Ray, who has done a good job of just pushing him to become better every day so I'm really happy for him."

Perkins received four votes to be named to one of the NBA's two All-Defensive teams last season.

"With Perk, we want him to be a deep-post guy," Boston coach Doc Rivers said. "When he catches it in the paint...Perk gets a lot of his post-action after he sets a pick for Paul [Pierce] or Ray [Allen] where the bigs on the other team has to help, and that allows him establish himself in the paint. When he catches it outside of the paint, he struggles a little bit. But when he gets it in the paint, he's very difficult to [defend]."

Rivers said that in Perkins' first three years in the league, he wanted to be an offensive player. But after the Celtics signed Kevin Garnett and Ray Allen, Perkins decided to become the best defensive player he could be because that is where he can help out the team the most.

"Perk has accepted his role and he is trying to master that role to make him a great player," Rivers said. "He's a defensive player and he knows that."