After a long and eventful road to the N.B.A. finals, Golden State was grateful for a full week to rest and recover before facing the Boston Celtics in Game 1 on Thursday night. 

Golden State’s modest break came to an abrupt end. Boston made sure of  it, stunning Golden State, 120-108, to take the opening game of the  best-of-seven series at Chase Center. 

The Celtics leaned on their depth to erase a 15-point deficit in the  second half. Al Horford scored a team-high 26 points, while Jaylen Brown  added 24 and Derrick White scored 21 off the bench. 

Jayson Tatum scored just 12 points in the win while shooting 3 of 17  from the field, but he had a game-high 13 assists. The Celtics also  managed to overcome a turbocharged effort form Golden State’s Stephen  Curry, who scored 34 points. 

Golden State’s third-quarter runs can be demoralizing for opponents, but  the Celtics have fought back in a big way in the fourth quarter. Boston  outscored Golden State 23-11 to start the fourth quarter and tied the  game at 103.  

When Memphis Grizzlies guard Dillon Brooks smacked Gary Payton II while  Payton was midair, it broke the hearts of Payton’s teammates and  coaches.  

That play from Golden State’s Western Conference semifinal series was  deemed a flagrant 2 foul and caused Payton to break his left elbow.  There was some concern he would be out for the rest of the playoffs. 

Payton is beloved in Golden State because of his winding path to finally  finding an N.B.A. home at the age of 29. Coach Steve Kerr said Brooks’s  foul “broke the code” by causing an injury that could end Payton’s  season or, Kerr said, jeopardize his career. 

Shades of Game 1 of the Eastern Conference finals against the Miami Heat  for the Celtics here, when the Heat outscored the Celtics 39-14 in the  third quarter, while the Celtics outplayed them for the rest of the  game. 

In this case, Golden State outscored Boston, 38-24. Boston was prone to  long stretches of ineptitude during the regular season, which  contributed to its underwhelming start to the season.