Boston, MA -- (Sports Network) - Kevin Garnett scored 26 points and Paul Pierce added 22 as the Celtics beat Detroit, 88-79, in the opener of the Eastern Conference finals. Having been pushed to seven games in each of the first two rounds, against Atlanta and Cleveland, respectively, the Celtics remained unbeaten on their home floor in the postseason after nine contests. Rajon Rondo had 11 points and seven assists for Boston, which is trying to advance to the NBA Finals for the first time since 1987. Garnett had eight of his points during a big run in the third quarter, and finished with nine rebounds while shooting 11-of-17 from the field. Tayshaun Prince scored 16 points and Richard Hamilton had 15 for the Pistons, who are into the East finals for a sixth straight year. Antonio McDyess tallied 14 points and 11 rebounds for Detroit, while Rasheed Wallace scored 11. Chauncey Billups, who missed the final two games of Detroit's second-round playoff series with Orlando due to a strained right hamstring, was limited to nine points. Game 2 of the best-of-seven series is scheduled for Thursday night, again at TD Banknorth Garden.