Piya had already made six birdies and an eagle when he rolled in a tricky 15-foot to pick up another shot on the final green and snatch the lead for the first time, drawing a flurry of fist pumps and cheers from the crowd.
But overnight leader Hend quickly responded, rolling in a birdie two on the 14th at Black Mountain Golf Club in Hua Hin where he was runner-up a year ago.
The big hitting Australian, whose previous European Tour win came at the 2014 Hong Kong Open, then drove the green with his tee shot at the 330 metre par-four 17th and walked away with a key birdie after a solid short putt to go ahead for good.
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More power hitting saw him find the green in two at the par five last as he took three putts to close out victory at the $1.75 million event and become the fifth different Australian winner in 13 European Tour events this season.
Belgium's Thomas Pieters (68) finished third on 15-under, with American Peter Uihlein (70) fourth and Swede Pelle Edberg (70) fifth at the event co-sanctioned with the Asian Tour.
(Writing by Patrick Johnston in Singapore; editing by Amlan Chakraborty)
