Up until now, the Celtics have known Greg Monroe as one of the players most likely to tear them apart in the paint. Last night, seven games into the center’s new life as a Celtic, they now have a better idea of what he can do for them. Monroe scored all 14 of his points in the paint on 6-for-9 shooting in the C’s 134-106 win over Charlotte, including the team’s first three possessions in the second quarter when Monroe successfully posted up each time against the Hornets’ Willy Hernangomez. “I feel like I got into a pretty good rhythm. Coach (Brad Stevens) went to me and I tried to be aggressive,” he said. “He said take your time, get your legs back under you, and tonight I got into a good rhythm that made me more comfortable. Pretty decent game. “It was fun. I know these fans expect the team to play at a high level, and like I’ve been saying, I just want to come in and enhance what they’ve already got going,” Monroe continued. “It’s been tough for me getting into a rhythm, especially with the situation this year, but it felt good to be out there in the flow of the game, and just be as effective as possible.” After not making it off the bench during Monday’s win over Memphis, Monroe showed up for an informal, intense workout on Tuesday with two of his rookie teammates — Semi Ojeleye and Abdel Nader.