Malaysia widened their lead over Singapore to five places after the release of the latest FIFA rankings.
Despite both nations losing their most recent Asian Cup qualifiers, Malaysia rose one spot to 166th, as Singapore fell two to a worst-ever 171st.
Singapore's current position is 51 spots below their average of 120th since the FIFA rankings began in 1993.
Their best ranking in the last decade came in 2009 when the Lions were 110th in the world.
While Malaysia's 166th is comfortably better than Singapore, it is still 36 spots worse than their average of 130th. Their highest position in the last 10 years came in 2011 when they were 138th.
Philippines remain Southeast Asia's top nation at 127th, despite dropping one spot in July. Reigning AFF Suzuki Cup champions Thailand are three positions behind in 130th after climbing one rung.
Vietnam (134th) and Myanmar (157th) are also above both Singapore and Malaysia, along with their upcoming AFC Asian Cup qualifying opponents Hong Kong (146th) and Turkmenistan (141st).
The top AFC nation remains Iran in 24th, but Japan (44th) have overtaken Asian champions Australia (45th), followed by South Korea (49th), Saudi Arabia (59th), United Arab Emirates (74th) and China (77th)
Follow @ESPNFC on Twitter to keep up with the latest football updates.