The final birdie -- one of six on the day for Larrazabal -- gave him a fourth-round score of 5-under-par 67 and a 72-hole total of 14-under 274.
That was one better than Rory McIlroy, who shot 68 Sunday, and Phil Mickelson, who turned in a final-round 69. George Coetzee had a bogey-free 66 and finished tied with Rafa Cabrera-Bello for fourth at 12-under. Cabrera-Bello shot 68 Sunday, a round that included a bogey at the ninth hole where he was 4-over for the week.
Third-round leader Craig Lee had three bogeys and a double bogey in a 5-over 77 Sunday, plummeting into a tie for 10th.
McIlroy had five birdies and a bogey Sunday but it was a two-stroke penalty assessed after Saturday's round that knocked him back. Mickelson was coming off a near-course-record 63 in the third round but he was staggered by a triple-bogey 7 at the 13th hole that even three birdies in the final five holes couldn't bring him back from.
Larrazabal's only slip Sunday came at the fifth hole where he had a bogey. Three birdies on each side, including the closing 5-footer, gave him his third European Tour title and first win since June 2011.