SAN FRANCISCO (AP) — The ball was moving, the shots were falling and the arena was rocking in a very familiar third quarter for the Golden State Warriors.

Then came the fourth quarter and a surprising collapse by the more experienced team as the Warriors dropped a rare Game 1 of a playoff series under coach Steve Kerr, losing the opener of the NBA Finals 120-108 to the Boston Celtics on Thursday night.

The Warriors turned a 12-point lead after three quarters into an 12-point loss in a shocking turnaround that silenced a boisterous crowd that had been celebrating Golden State’s return to the Finals after a two-year absence.

Boston made its first seven 3-pointers of the quarter and ran away, leading to chants of “Let's Go Celtics!” in the closing seconds in a half-empty arena. The Warriors scored just 16 points in the fourth quarter after a 38-point explosion in the third had put them seemingly in control.

The meltdown left the Warriors complaining to officials and searching for answers after their first home loss in these playoffs after opening with nine straight wins.

It was the biggest blown lead after three quarters of an NBA Finals game in 30 years as the experienced Warriors fell apart down the stretch instead of a Celtics team filled with Finals newcomers. The last team to lose a Finals game when leading by at least 12 points after three quarters was Portland in 1992 in a Game 6 series-ending loss to Michael Jordan and the Bulls.

The Game 1 loss was just the third in 24 playoff series for the Warriors under coach Steve Kerr with the others coming in the 2019 Finals against Toronto and the 2016 Western Conference finals against Oklahoma City.

It also overshadowed what had been a blistering start by Stephen Curry, who made a Finals record six 3-pointers and scored 21 points in the first quarter.

But the Celtics adjusted and Curry made just one 3-pointer and scored 13 points the rest of the way.

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