Tim Duncan couldn’t bear to look. Tiago Splitter couldn’t have looked if he wanted to. Vince Carter had the best view of all, seeing as the last-second shot had come from his fingertips. In the moment just after his final 3-point try went airborne, did the Dallas forward believe he had just dealt the Spurs a heartbreaking loss at the buzzer Thursday night? “Damn right,” Carter said. Instead, the ball bounced once off the right side of the rim, once off the back and caromed out, preserving for the Spurs a 92-91 victory at the AT&T Center. Not all the Spurs were aware just how close they came to blowing a game that, with 2 1/2 minutes left, seemed all but formality. As Carter’s shot went up, Duncan — on the sidelines due to a defensive substitution for the final 8.7 seconds of his best game in more than a month — looked away and crossed his fingers. Splitter, who had switched on Carter to disrupt the final attempt, didn’t have time to turn around to see the result. “I just contested,” Splitter said, “and prayed.” If the recent election of a pope from South America helped the Brazilian’s Hail Mary find a willing ear, we’ll never know. In the thick of a race for the Western Conference’s top seed, the Spurs will light an extra candle in gratitude for this one not slipping away. Behind Duncan’s most dominating night since spraining his knee Feb. 2 at Washington, and a timely scoring flurry from reserve guard Gary Neal, the Spurs won their 50th game for the 14th consecutive season, extending their own NBA record. They are 50-16 now, matching their West-leading finish from last season’s lockout-shortened campaign. After another uneven performance in a March pockmarked with them, however, the Spurs were in no mood to celebrate that accomplishment.