"It is a momentous occasion," Bhutan Football Federation president Ugyen Tsechup Dorji told BBC World Football.
"Sri Lanka is a team that is not way, way beyond the quality level of football that is being played in Bhutan. It will depend on that particular day, how our boys perform, and we are hopeful."
Bhutan have only three wins to their name -- against Afghanistan, Montserrat and Guam -- and were beaten 5-2 by Sri Lanka in their last international match at the 2013 South Asian Football Championships in Kathmandu.
Bhutan's squad of semi-professionals warmed up for the crunch clash with a training camp in Thailand to prepare themselves for the hot conditions they will face in Sri Lanka.
Dorji said his side, once tonked 20-0 by Kuwait in an Asian Cup qualifier in 2000, were unconcerned about the world's worst team tag and the lack of fixtures did not mean the sport was being neglected.
"We are not bothered by the FIFA rankings. In reality, the teams that are 160, 170, 180 right up to 207, 208 you really don't need to win games to improve your FIFA ranking," he said.
"But Bhutan, we have made a very conscious decision... to try and improve the youth and grassroots programs rather than to send our teams outside the country to participate to play championships and matches so that our FIFA ranking is at a higher level."
The inclusion of Bhutan mean it is the first time all 209 FIFA members have attempted to qualify for a World Cup, the world governing body said.
A shock victory for Bhutan's side, filled with mainly office workers who earn on average around $60-$70 a month for playing football, would take them through to the second round where the likes of Asian champions Australia, Japan and Iran enter the draw.
Also playing on Tuesday are Bhutan's neighbours India, who host Nepal with the lengthy qualifying process also determining the teams that will play at the 2019 Asian Cup.
Long dubbed the sleeping giants of world football, India have recalled Englishman Stephen Constantine as coach and although Russia will be a step too far they do hold hope of making the 24-team Asian Cup.
"It's an absolute must for India to win this game, and that's what we'll try and do," the former Nepal coach told reporters last week.
India and Pakistan, who play away to Yemen on Thursday, are the best ranked sides taking part in this first stage of qualifying at joint 171st in the FIFA table.
Elsewhere, East Timor host Mongolia, Taiwan face Brunei and the gambling enclave of Macau travel to play Cambodia.
(Writing by Patrick Johnston in Singapore; editing by Sudipto Ganguly)
