Curry, who went into the contest with an average of 32.2 points per game, made just nine of 27 shots from the floor.
Fiercely defended by the Celtics, he made eight turnovers and his two free throws were his only points of the second overtime.
"Nothing was pretty about this game," said Curry, who did make six of 13 three-point attempts and all 14 of his foul shots en route to 38 points.
"But we got stops, everybody contributed ... considering all the injuries we had and this being the end of the road trip - huge win for us."
In Orlando, Cleveland downed the Magic 111-76, with LeBron James scoring 25 points to help bring up a 12th consecutive victory over their hosts. James hit 10 of 15 shots and added eight assists. He sat out the fourth quarter after Cleveland took an 83-52 lead through three.
Reggie Jackson and Marcus Morris scored 21 points apiece as Detroit beat Philadelphia 107-95. Morris had 13 points in a decisive third-quarter stretch as the Pistons (13-11) ended a four-game road losing streak and a three-game slide.
In Indianapolis, Monta Ellis scored 24 points and Paul George added 23 to lead Indiana to a 96-83 victory over Miami. It was the ninth consecutive time the Pacers (13-8) had beaten the Heat (12-9) at Bankers Life Fieldhouse.
DeMar DeRozan scored 27 points as Toronto defeated Milwaukee 90-83, the third win in a row for the Raptors (15-9) and the second loss in a row for the Bucks (9-15).
Tyreke Evans scored 27 and Anthony Davis added 18 and 11 rebounds as New Orleans made a franchise-record 16 three-pointers to defeat Washington 107-105.
Kemba Walker scored 33 points and Nicolas Batum had 20 as Charlotte defeated Memphis 123-99.
Elsewhere, Oklahoma City thwarted a late rally by Utah for a 94-90 win, Portland brought up a 106-96 victory over Phoenix, San Antonio downed the Los Angeles Lakers 109-87 and Denver rallied to beat Minnesota 111-108.
-AAP
