Boston ? Doc Rivers laughed. Paul Pierce smiled. The emotional shock of a tough day had worn off for the Boston Celtics.

More than 24 hours had passed since they learned that Kevin Garnett would miss the first round against the Chicago Bulls, and probably the rest of the playoffs, and that general manager Danny Ainge suffered a heart attack that later was described as minor by the team.

The mood had lightened enough Friday for second-year forward Glen “Big Baby” Davis to joke about his role as the replacement for “The Big Ticket,” Garnett’s nickname, in today’s series opener.

“I’m not the Big Ticket. I’m the Ticket Stub,” Davis said with a grin. “So don’t count the Ticket Stub out. You might need the ticket to get into the game, but you leave with the ticket stub because you’ll never forget this game. You need it as a souvenir.”

Rivers doesn’t expect to coach Garnett again this season; he’s out with a strained tendon in his right knee. Without his defense and leadership, the second-seeded Celtics’ mission to repeat as NBA champions will be a lot more difficult. Even with him, they needed seven games to get past Atlanta in the first round last year. Every opponent this season has been motivated to knock off the champions.

“We’ve been tried all year,” Pierce said. “For us to repeat, it’s going to be the toughest thing we ever had to do.”