Singapore dropped 4 places to 158 in the FIFA rankings for February, just a week after their 0-4 loss to Jordan, who moved three spots to 92 in the world.
Led by interim coach V.Sundramoorthy, the Lions fell in the opening match of the AFC Asian Cup qualifier in Amman, days after losing 3-1 to Bahrain in a warm-up friendly.
Asian giants, Japan, have dropped seven positions to 28 but still remain top of Asia. The Blue Samurais are trailed by Australia and Korea who are at the 37th and 38th spot respectively.
Singapore, meanwhile are ranked 25th in Asia behind the likes of Hong Kong, Philippines and Thailand. The AFF Champions are ranked fourth in Asean with Malaysia, who are ranked 159th overall, in fifth.
Cambodia were the only South East Asian nation to move up the rankings as their meagre improvement of one spot brought them up to 183, while Vietnam remained the highest ranked in South East Asia at the 134th spot.
England has managed to squeeze themselves into 4th after their 2-1 win over Brazil last week, which pushes Italy down to the 5th spot. The top 3 remains unchanged with Spain strengthening their foothold at the top of the rankings with a win over Uruguay while Germany and Argentina complete the top 3 respectively.
The biggest movers overall were the African nations following the conclusion of the Afcon 2013. Champions Nigeria moved up 22 spots to 30th, while runners-up Burkina Faso climbed a massive 37 places to 55th. Hosts South Africa also made leaps going up 25 places to 60th.