The world's lowest-ranked team, Bhutan, pulled off a seismic shock on Tuesday when they overcame Sri Lanka to reach the second round in their first ever World Cup qualifying campaign.

Two goals from "the Ronaldo of Bhutan," Chencho Gyeltshen, ensured a 2-1 win in the second leg and a shock 3-1 aggregate victory, sparking wild celebrations in the capital Thimphu.

The striker opened the scoring on five minutes and he was mobbed by his team-mates when he coolly struck the winner in the 90th minute, sealing Bhutan's progression.

The victory at Changlimithang Stadium follows last week's 1-0 win in Colombo and comes after ex-Sri Lanka captain Ashok Nawgalage even questioned the point of playing Bhutan.

But now the tiny Himalayan kingdom, who prop up the FIFA rankings at 209th in the world, take their place in the group stage involving 40 Asian teams.

Theirs was not the only fairytale win as East Timor, one of the world's youngest and poorest nations, sent Mongolia crashing out 5-1 on aggregate in chilly Ulan Bator.

Sleeping giant India made it through thanks to a 0-0 draw with Nepal in Kathmandu, following last week's 2-0 victory in the east Indian city of Guwahati.

But Pakistan's home leg against Yemen in Lahore was postponed and shifted to an as-yet-unnamed neutral venue after a deadly Taliban attack on churches in the city.

The move was another blow to sport in Pakistan, who trail 3-1 from the first leg, after a 2009 attack in Lahore put tours by international cricket teams on hold.

Asia's lowest-ranked teams are playing home and away to reach the group stage starting in June, kicking off a marathon, worldwide qualifying campaign for the 2018 World Cup in Russia.