With the Celtics well on their way to a 99-86 win over Golden State, an opposing player was receiving the Stephen Curry treatment — a sight not before seen in the Steve Kerr era. With Kevin Durant watching from the locker room, the Warriors again were undone by fourth-quarter issues. With the eight-time NBA All-Star sidelined at least another three weeks by a left knee injury, Golden State limps into a back-to-back set in Minnesota and San Antonio with a 1½-game lead over the Spurs for the top seed in the Western Conference. San Antonio, which overcame a 28-point, first-half deficit Wednesday without Kawhi Leonard and LaMarcus Aldridge to beat the Kings, gets the tiebreaker if it wins one of its two remaining games against the Warriors. With the third-quarter clock winding down, Curry dribbled left, threw off Boston rookie Jaylen Brown with one of his signature moves and nailed a three-pointer from the top of the arc. The two-time NBA MVP smiled as he pointed at Brown, hammering home a lesson: [...] after a Draymond Green dunk put Golden State up 79-78 with 7:18 left, old problems — stagnant offense, lackadaisical offensive rebounding, slopping passing —...