SAN FRANCISCO — The Boston Celtics’ reaction to winning Game 1 of the N.B.A. finals on Thursday night was a marked contrast from the joyous celebration they had held after winning Game 7 of the Eastern Conference finals earlier in the week. Instead of chest bumps at midcourt after the final buzzer, the Celtics walked stoically off the court on Thursday, each player stone-faced, some engrossed in conversations with coaches.
This stage was supposed to be too big for these Celtics, a team, though not a franchise, that was new to the finals. There were supposed to be jitters once the series started for this band of mostly 20-somethings facing a veteran Golden State Warriors team that has been here plenty of times.