The 44-year-old, who is the only Thai at this week's Masters, said his physical fitness and recent form should be good enough to send him to the weekend rounds for the first time at Augusta.
Thongchai has made the cut at the other three major events and is desperate to play at Augusta this weekend.
"I want to be the first Thai to make the cut at the Masters," said the Lop Buri native, who previously played at the Masters in 2006 and 2010.
"I have played in all four rounds of the other three major championships but not at the Masters. It is my goal to make the halfway cut this time so that I get to complete my own Grand Slam of made cuts in the majors."
He qualified for the previous two editions as the Asian Tour's top player, and this time earned an Augusta berth thanks to his top-50 spot in the world rankings at the end of last year.
He said he failed in 2006 because Augusta was a new experience for him and was unsuccessful in 2010 because he was forced to withdraw due to a back injury.
"I am ready for this year's tournament," he said. "I hope it will be third time lucky."
Currently ranked 51st in the world, Thongchai has had a good spell this year, finishing tied for sixth at the WGC-Cadillac Championship.
Thongchai said the most challenging part at Augusta was the greens.
"My iron play is good but I have to improve my putting to handle the greens," he said.
"We all know that the greens at Augusta are very tricky, very hard to putt on.
"I have been working hard on my putting and hope to spend as much time as possible on the greens at Augusta to know them better.
"If I can putt well, then I know I will have a chance to compete well during the week.
"When I played at Augusta twice previously, I found it a real challenge to putt well on the greens."
His confidence has been boosted after he masterminded Asia’s stunning fightback to share the inaugural EurAsia Cup with Europe two weeks ago in the Ryder Cup-style match in Malaysia.
Thongchai's best performance in major tournaments was joint 13th at the 2009 British Open. He was also tied for 47the at the 2010 US Open and shared 36th at the 2009 PGA Championship.
Thongchai is eligible to play in all four majors this year.