Pierce

BOSTON — Paul Pierce was fired up.

Boston’s captain and All-Star forward was all business because the Celtics entered last night’s game on a two-game losing streak.

He was fired up because he hadn’t played up to his potential in any of the Celtics’ playoff games leading up to last night’s Game Five, and he was fired up because he was fined $25,000 for a Game Three hand gesture that he felt was harmless, not gang-related like NBA officials believe.

Pierce took his frustration out on Atlanta last night, torching the Hawks for 22 points, 7 rebounds and 6 assists to help lead Boston to a 110-85 triumph before a sellout crowd of 18,624 at the TD Banknorth Garden.

“Pierce got it started for them early,” Atlanta forward Josh Smith said. “At the beginning of the games lately he hasn’t been getting himself involved in the offense early on, and that’s probably been the cause of him not doing well. He made it an issue to get out early and get easy buckets.”

Pierce had been the subject of criticism by NBA commissioner David Stern earlier this week for the “menacing gesture” he signaled to the Hawks’ bench after Atlanta forward Al Horford scored the final basket of Game Three and then got in the face of Pierce while Pierce was on the floor.

Pierce got up slowly, walked toward midcourt and threw up what NBA officials believed to be a gang sign. Pierce formed a circle with his right thumb and index finger and extended his three other fingers before being pulled away by teammate Brian Scalabrine.

The hand signal is similar to the gang sign used by the Piru Bloods in Pierce’s hometown of Inglewood, Calif.

It’s also consistent with “three’s up” or the “B” hand signal used by Boston teens to represent the Hub. Pierce and the Celtics have denied that the gesture is gang related.

“I would say that the league is sending a message that says, ‘You’re the best athletes in the world. Play the game,’ Stern said. ‘If you get baited, don’t take the bait. Let’s play. Let’s show what you’ve got, which happens to be the most extraordinary athletes playing a spectacular game. We’re not going to let it degenerate into something else. Period.’ ”

Earlier this week Boston coach Doc Rivers said he believes Pierce should appeal the fine, but that probably won’t happen until the season is over.

Pierce said in a statement last night, “I don’t want to take the focus away from the playoffs. In sports, emotions run high. After playing for 10 years in Boston, I think Celtics fans know that I am a passionate player.

“I 100 percent do not in any way promote gang violence or anything close to it. I am sorry if it was misinterpreted that way at Saturday’s game. In fact, through my Truth foundation I am committed to giving back to youth groups and making sure young people have the opportunities to succeed in life.

“I am extremely proud of the work I have done through the foundation to provide positive influences and safe havens for inner-city kids.”

The Celtics say the gesture stands for “blood, sweat, and tears.”

“We’ve talked about it from Day One; that’s what it takes to get the job done, and that’s what it takes to win,” said Boston guard Rajon Rondo, who added that he, too, makes the gesture. “That’s what Pose (Boston forward James Posey), that’s what his motto was in his series when he won the championship [with Miami].

Every game, he does blood, sweat and tears,” Celtics executive director of basketball operations Danny Ainge said earlier this week. “That’s kind of his sign. It’s not anything related to anything. That’s what he does. Every single game during the introductions.”

roblee@projo.com