Tim Duncan was delivering a vintage performance, and the San Antonio Spurs were streaking to the franchise's fifth championship. Then the 37-year-old forward ran out of gas, and the Spurs collapsed down the stretch like they so rarely have before. Duncan had 30 points and 14 rebounds in the first three quarters, but was scoreless and grabbed just three boards in the fourth quarter and overtime of San Antonio's 103-100 overtime loss to the Miami Heat in Game 6 of the NBA Finals on Tuesday night. The Spurs led by 10 points at the start of the fourth quarter and by five with 28 seconds to play. But Duncan missed all five of his shots in the fourth quarter and overtime and Ray Allen hit a 3-pointer with 5.2 seconds to play in regulation that kept the defending champions alive. "I have no clue how we're going to be re-energized. I'm devastated,'' Ginobili said. "But we have to. There's no Game 8 afterward. We're going to have to play our best game. ... There's no secret recipe for bouncing back.''