Fernandez-Castano, even with the closing 6 in the par-4 18th, was 4-under-par 68 Sunday and had a 72-hole total of 11-under 277. That was one stroke better than Francesco Molinari, who was 6-under over the final six holes for an 8-under 64, and Thongchai Jaidee, who shot 66 Sunday.
Third-round co-leader Luke Guthrie only managed a 1-under 71, which pushed him to a fourth-place finish at 9-under. The other leader after 54 holes was Rafael Cabrera-Bello but he had a 73 Sunday that dropped him out of contention.
Molinari, playing well before Fernandez-Castano, put the pressure on with a five-hole string that including an eagle at the par-5 13th and then four birdies to get to 10-under.
Fernandez-Castano had birdies at 7, 8 and 11 that pulled him to 10-under and than went ahead for good with a birdie at 13. He pushed his advantage to three strokes with birdies at 15 and 17 before twice finding bunkers en route to a 6 at the closing hole.
Sunday marked the seventh European Tour win for Fernandez-Castano. He collected nearly $1.2 million along with the title. Jaidee and Molinari each took home more than $600,000 as runners-up.