The Giants took the lead in the top of the final frame by scoring four runs, but after Shawn O'Malley reached first on a single, Calhoun brought him in with a timely homer to win the game.
Erick Aybar and Calhoun both had two hits while Howie Kendrick drove in two runners for the Angels. Starter Hector Santiago allowed three runs on four hits with five strikeouts across 5 1/3 innings.
Chris Dominguez went 2-for-2 and Ryan Lollis' triple drove in two runs for the Giants. Tim Lincecum was reached for five runs on seven hits in 5 1/3 frames.
Kole Calhoun's two-run blast in the ninth inning proved to the deciding factor as the Los Angeles Angels defeated the San Francisco Giants, 8-7, in spring training on Monday.