Paul Pierce scored 34 points, including a 3-pointer at the start of the second overtime to give Boston the lead for good, and the Celtics held on to beat the Dallas Mavericks 117-115 on Wednesday night.
Rajon Rondo had 16 points, 15 assists and nine rebounds, and Kevin Garnett added 16 points for Boston.
O.J. Mayo scored 24 points for Dallas, and Shawm Marion had 16 points, 11 rebounds and seven assists.
Pierce made five of six free throws in the second overtime to help clinch the Celtics' second straight victory. With his basket with 59 seconds left in the first overtime, he surpassed 23,000 points in his career. He is the 25th player in NBA history to reach the mark.