The Celtics entered the season as the defending Eastern Conference and Atlantic Division champions, with hopes of claiming a record-breaking eighteenth NBA Championship, having lost to the Golden State Warriors in six games in the 2022 NBA Finals the season prior.
[4] After 42 wins in the first 59 games of the season, Mazzulla was named the permanent head coach and signed to a contract extension on February 16, 2023.
In this round, Boston faced their rivals the Miami Heat for the third time in four years, and quickly found themselves in trouble, going 0–3 down in the series, a position from which no team had ever advanced before.
However, the Celtics refused to give up, and became only the fourth team in NBA history to force a Game 7 from such a position when Derrick White made a dramatic buzzer-beating putback layup at the end of Game 6, the first buzzer-beater made by a team trailing and facing elimination since Michael Jordan's famous 1989 shot against the Cleveland Cavaliers.
Despite hopes of becoming the first NBA team to overcome a 0–3 series deficit, Boston failed to make history in Game 7, collapsing in a 103–84 home loss, during which Jayson Tatum injured his ankle in the first minute of the game and ending their season just one win short of a return to the NBA Finals.