Chawrasia, runner-up at the Hero Indian Open earlier this year, was fourth overnight but slipped with a double bogey on par-4 fourth. However, he had pars before and after till that he birdied 14th, 16th and 17 to shoot one-under 70 and total seven-under 281.
It was Chawrasia's third Top-10 finish in four starts on Asian Tour this season and he stands fourth and Anirban Lahiri leads the Money List by a big margin of over USD 400,000 over Andrew Dodt.
Meanwhile, Thai veteran Prayad Marksaeng tamed the 'beast of Samui' for the second time in three years with a superb six-under 65 to win by two shots.
The battle-hardened Prayad overturned a three-shot deficit by firing nine birdies against three bogeys for a winning total of 14-under 270 at the Santiburi Samui Country Club.
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Chawrasia said, "I thought I had an outside chance, but the double bogey ruined it. I became a little careful after that then the putts fell towards the end. A Top-10 finish is nice, but I expected much more."
Thanyakon Khrongpha matched Prayad's efforts on the final day to grab second place while Jazz Janewattananond, made it a 1-2-3 for Thailand, at 274.
Siddikur Rahman of Bangladesh with 69-70-67-68 ended tied third, his fifth Top-5 finish at Queen's Cup, staged in honour of Her Majesty Queen Sirikit.
Mithun Perera of Sri Lanka carded a 69 to finish two shots back in fifth place.
Finishing tied sixth with Chawrasia were American Paul Peterson (68), Canadian Richard T. Lee (70) and Japanese Akinori Tani (75), who fell down from his overnight top place.