By the end of the off-season, only four Celtics' players remained from the 2016–17 team, with Marcus Smart being the longest tenured Celtic from the 2014 NBA draft. On the team's opening night game in the first quarter against the Cavaliers, Hayward suffered a fractured tibia and dislocated ankle in his left leg, causing him to be ruled out for the rest of the regular season. Despite the loss, the Celtics went on a 16-game winning streak, which also went down as the fourth-longest winning streak in the teams' history. The streak started with a 102–92 victory over the Philadelphia 76ers on October 20 and ended on November 22 to the hands of the Miami Heat with a 98–104 loss. The Celtics finished the year with a 55–27 record, good enough for second place in the Eastern Conference. In the playoffs, they defeated the Milwaukee Bucks in the First Round in seven games, and continued the feat in the Conference Semifinals by defeating the Philadelphia 76ers in five games before losing to the Cleveland Cavaliers in seven games in the Conference Finals.