ATLANTA — Rajon Rondo had 14 points, 11 rebounds and 10 assists, and the Boston Celtics rallied to beat the Atlanta Hawks 89-81 on Saturday night. Paul Pierce scored 17 of his 26 points in the third quarter as the Celtics erased a 19-point deficit and went on to consecutive wins for the first time since late November against Oklahoma City and Orlando. Boston, which beat Indiana 94-75 on Friday night, had lost four straight road games.