Quiros, a 25-year-old Spaniard, made back-to-back birdies to close out his final round at the Oceanico Victoria golf course with a total of 19-under-par 269.
He dedicated his win to European Tour great and countryman Seve Ballesteros, recovering from two operations to remove a brain tumor.
"Seve played in a different way of the rest of the world," Quiros said. "He was something special. It's been a really tough year for me (but) this is a little help."
Lawrie, a former British Open champion, closed with a 5-under 67, making his 72-hole total 16-under 272. At 15-under 273, Order of Merit leader Robert Karlsson (71), Ross Fisher (71) and 2007 champion Steve Webster (68) shared third.