With the Spurs trailing by a point, Ginobili took a cross-court pass from Kawhi Leonard on the left side and fired in a trey with 1.2 seconds left, boosting the Spurs to a marathon victory in the first game of their Western Conference semifinal series.
Ginobili, who had missed seven straight 3-point tries before the game-winner, finished with 16 points, 11 assists and seven rebounds.
Tony Parker provided 28 points, eight helpers and eight boards while Danny Green added six 3-pointers en route to 22 points for San Antonio, which went on an 18-2 run late in regulation to force an overtime.
Stephen Curry pumped in 44 points on 18-of-35 shooting and dished off 11 assists for the Warriors, who will try to bounce back in Wednesday's Game 2.
Swim Week Miami Beach 2014 [PHOTOS]