In recent times, Asia's richest national championship which is held at the Sentosa Golf Club has shaped the Merit race and with current leader Chowrasia struggling to find the form that won him the season-opening Avantha Masters, Thongchai and Singh are ready to pounce.
Thai star Thongchai, the only man to win three Merit crowns, said he would aim for top spot in the Barclays Singapore Open which will feature Major winners including Phil Mickelson, Ernie Els, Graeme McDowell, Padraig Harrington, Y.E. Yang and Retief Goosen.
"This tournament is important. It's a big event in Asia and it's important for Asian players. If someone wins this, you'll jump to number one. Every time, I'm thinking of the Order of Merit. I will try," said Thongchai, who is eighth on the Merit list.
Singh, Asia's number one in 2006 and 2008, used his famous victory at the Barclays Singapore Open to land the second of his Merit crowns, which rewards the champion with a spot in the British Open and WGC-Cadillac Championship.
"It's at the back of my mind," said the widely-travelled Indian. "This tournament made me win the Order of Merit in 2008. I'm thinking about it and will give it a go and see what comes my way. Winning the Order of Merit on any tour is fantastic especially in Asia where I started from," added Singh, who is currently ninth on the rankings.
Singh edged out Harrington and Els by one shot three years ago and a return to the Lion City often brings about good vibes. "Excellent memories. The way I won the tournament was fantastic and it gave me a lot of confidence. The course is excellent and I love Singapore as it's one of my favourite cities in the world. It's like New York. There's so much buzz in the city and that's what I love about Singapore. I take it down to the golf course with me," he said.
Thongchai is eager to add the Barclays Singapore Open to his record 13 wins on the Asian Tour but knows his putter must behave on the slick Sentosa greens. With poor putting being his Achilles heel all year, the Thai has tried out the belly putter but eventually settled for a putter with some three inches added to its length.
"I've got confidence coming back with the putting. My driving and irons are good. Last few events, I've been playing good. I'm happy now. You lose confidence and you can't play well," said Thongchai.
"For the past two years, I've been changing a lot with my putter. I used the belly putter for a month but it was difficult to putt on the long putts. Now, I'm back to the normal putter but it's slightly longer at 35 inches. The set-up is a bit more upright and it's a matter of reading the right lines now."
Chowrasia knows he must quickly remedy some poor form after being 14-over-par in his last two tournaments in Malaysia and China where he finished 47th and 65th respectively.
"This is an important week. I know I will have to play well to keep my lead as there is a lot of prize money to play for. I've not played well here in the past but I feel my game is coming around," said the Indian.
"Last week, I didn't drive the ball too well in Shanghai but putted well and in Malaysia, I drove beautifully but didn't putt too well. I need everything to click in my game and this week would be a good week to do so," added Chowrasia.