In 2010–11, Terry averaged 15.8 points, 1.9 rebounds, 4.1 assists and 31.1 minutes in 82 games (10 starts). He was the only Maverick to appear in all 82 games in 2010–11. On November 6, 2010, he scored 26 points against the Denver Nuggets. He scored 23 of his 26 points in the 1st half, the most he's recorded in the first half of a game in his career (previous high 22, against the Portland Trail Blazers on April 7, 2007). In the West Conference Semifinals against the Los Angeles Lakers, Terry scored a playoff-high 32 points in Game 4. His 9 3-pointers tied an NBA playoff record held by Rex Chapman, who set it in April 1997 with the Phoenix Suns. It was surpassed by Klay Thompson (11) in 2016 and Damian Lillard (12, 2OT) in 2021. As of 2022, it still stood as the most by a reserve in a playoff game. The Mavericks went on to advance to the NBA Finals for just the second time in franchise history. In the 2011 NBA Finals, against the Miami Heat, Terry averaged 18.0 points, 2.0 rebounds, 3.2 assists, 1.3 steals and 32.5 minutes over the six games. He recorded 21 points, 4 rebounds and 6 assists in 30 minutes in Game 5 to become the first sub to record at least 20 points and 5 assists in a Finals game since Michael Cooper in 1987. Terry had a game-high 27 points in 34 minutes in the series-clinching Game 6 to claim his first NBA Championship. In the lockout-shortened 2011–12 season, Terry averaged 15.1 points, 2.4 rebounds and 3.6 assists while shooting 37.8% from three-point territory. He finished second in the league with 138 made three-pointers and was third in the NBA in three-point field goal attempts (365). He concluded his time in Dallas with the fourth-most three-point shots in NBA history with 1,788, trailing only Ray Allen, Reggie Miller and teammate Jason Kidd. Boston Celtics (2012–2013) On July 18, 2012, Terry signed a multi-year deal with the Boston Celtics. He averaged 10.1 points, 2.0 rebounds, 2.5 assists and 0.84 steals in 26.9 minutes per game during the 2012–13 season. He recorded his first double-double as a Celtic with 17 points and season-high 11 assists to go along with three steals against the Milwaukee Bucks on December 1, 2012. He scored a season-high 26 points against the Denver Nuggets on February