Matthew finished at 12-under 276, collecting her fourth career LPGA Tour win. She held an eight-shot lead at one point and was never seriously threatened despite a late letdown.
Matthew finished in the 60s in three of her four rounds, gaining only her fourth Top 5 finish of the year over the course of 18 events.
Tied for a distant second at minus-8 were defending champion I.K. Kim (71) and Anna Nordqvist (71).
Three shots further back at minus-5 were Hee Kyung Seo (69), Ai Miyazato (71) and Juli Inkster (72).