Spangenberg, selected Monday from Double-A San Antonio as part of San Diego's September callups, made a diving stop with runners at first and second base in the first inning to potentially save a run.
Alexi Amarista also drove in a run for the Padres, who were coming off a 7-1 loss to the Dodgers on Sunday after winning their previous three games with walk-off hits in extra innings.
Tyson Ross (13-12) threw six innings and gave up one run in his 14th straight quality start, extending his Padres record. The right-hander struck out eight, walked two and surrendered six hits.
Kevin Quackenbush fanned all three batters he faced in the ninth inning to earn his second save.
Two of those batters, Arizona third baseman Jake Lamb and left fielder Nolan Reimold, each struck out four times in the game.
Trevor Cahill (3-10) took the loss after giving up three runs on five hits and six walks in four-plus innings. It was Arizona's 11th loss in 15 games.