The win is only the Spaniard’s third (the Singapore Masters on the Asian Tour is the other) since he donned the green jacket at Augusta National 18 months ago.
An eagle at the 72nd hole propelled Matthew Griffin to his third top-10 finish in Japan this year, while Jack Wilson recorded his best finish on the European Challenge Tour at the Foshan Open in China.
Koepka entered the tournament ranked third in the world, but with a victory or a solo second without Thomas winning, he can jump Dustin Johnson and Justin Rose to become No.1.
Four successive top-10 finishes has the 22-year-old sitting 14th on the Order of Merit and with some significant ramifications looming based on his result in Lima.