A disastrous front nine saw Anirban Lahiri falter in the final round of the Queen's Cup and lose the chance of making a bid for his first Asian Tour outside his home turf.
Lahiri with a final round of 75 totalled four-under 280 and finished in a tie for 10th place.
Lahiri dropped no less than three bogeys and a double bogey in his five-over 41 for the front nine. Birdies on 15th and 18th just about ensured a top-10 for Lahiri.
Rahil Gangjee also suffered a setback on the final with five-over 76 that saw him drop to tied 47th.
Meanwhile, Prayad Marksaeng finally tamed the beast of Samui when he landed two eagles as he edged out compatriot Arnond Vongvanij by three shots to win the Queen's Cup on Saturday.
Having come close with three top-three finishes since the Queen's Cup made its debut on the Asian Tour in 2009, Prayad by closing with a eagle to win with a final round four-under-par 67.
Arnond applied the pressure on Prayad by firing two birdies in his last three holes but it was not enough to catch the 47-year-old veteran who signed off with a four-day total of 14-under-par 270.
Arnond enjoyed his second top-10 finish of the season by carding a 69 to take second place while Japan's Daisuke Kataoka posted a 68 to secure third place with a 275 total.
Backed by the passionate home crowd at the Santiburi Samui Country Club, Prayad started the day in second place, one shot behind Bangladesh's Siddikur, who also stumbled with a 77 and ended eighth.
Prayad stumbled with an opening bogey but birdied holes four and six to take over the lead. Prayad dropped another shot on the seventh but a spectacular eagle-three on the eighth hole saw him extend his advantage to two at that stage.
Arnond came into the final round hoping to add the Queen's Cup to the King's Cup which he won during his rookie year last season.
Having held the lead for two rounds, Kataoka was looking for his career breakthrough on the region's premier Tour this week. However he posted his week's highest score of 74 in the third round and found himself five shots back of the leader, heading into the final round.
Sanctioned by the Asian Tour and Thailand PGA, the Queen's Cup is held in honour of Her Majesty, Queen Sirikit and is one of four tournaments in Thailand to feature on the Asian Tour, which is celebrating its milestone 10th season after establishing itself as a players' organisation in 2004.