ith the blessing of coach Jim O'Brien, Antoine Walker took over the Celtics huddles in the fourth quarter last night. The power forward offered his teammates a simple message: ''Don't let what happened in Detroit happen again. Play loose. Play smart. Don't force things.''

They listened well.

With a final frame marked by intelligent execution, the Celtics surged to a 106-97 victory over the Toronto Raptors at the FleetCenter. Boston shot 66.7 percent in the fourth period, making smart passes and raising the energy level. The team's play was in complete contrast to the fourth quarter against the Pistons Saturday night, when it squandered a 17-point lead and lost the game.