BANGKOK, January 19, 2014 (AFP) - Prayad, who took the Queen's Cup in June, claimed another victory at the Asian Tour season-ending event with a total of 12-under-par 276.
Rikard Karlberg of Sweden, who had taken a share of the lead for the first two rounds, was forced to settle for second place after ending with a 67.
Thailand's Prom Meesawat, who posted a final-round 71, finished equal third alongside compatriot Chapchai Nirat and India's Anirban Lahiri.
"I'm extremely happy to win the King's Cup because it's a great event and also staged in my home town here in Hua Hin. This win is especially special as it's dedicated to all the Thai people," said Prayad in comments supplied by the organisers.
He took home the winner's prize purse of US$180,000 to surpass the US$3 million career earnings mark on the Asian Tour.
Prayad started with three birdies in his opening four holes.
After turning in 34, he birdied the par-four 10th to move within two shots back of Karlberg at nine-under.
Cheers from the crowd erupted when Prayad sank his eagle putt from 20 feet to topple Karlberg from the lead after the Swede succumbed to nerves and made consecutive bogeys on holes 13 and 14.
Prayad's eighth win on the Tour was confirmed after another birdie on the 17th ensured his victory, which he celebrated by jumping into the ninth-hole greenside lake.
Leading scores after the final round:
276 - Prayad Marksaeng (THA) 68-71-71-66
277 - Rikard Karlberg (SWE) 65-71-74-67
279 - Anirban Lahiri(IND) 69-71-71-68, Chapchai Nirat (THA) 68-73-68-70, Prom Meesawat (THA) 65-71-72-71
280 - Mardan Mamat (SIN) 71-70-71-68
281 - Scott Hend (AUS) 72-71-69-69, Angelo Que (PHI) 66-75-67-73
283 - Daisuke Kataoka(JPN) 73-69-72-69
284 - Andrew Dodt (AUS) 71-73-71-69, Mo Joong-kyung (KOR) 69-68-70-77