Singapore slide to lowest-ever position in FIFA rankings
The Lions have slumped 11 places to sit two spots below their previous low point of 171st, set in October last year and again in August 2017.
Sundram's side have yet to win since beating Cambodia 1-0 in a pre-Suzuki Cup friendly back in November 2016
V. Sundramoorthy's men were ranked 162nd last month, four spots ahead of rivals Malaysia. The Tigers are currently tied for 170th with Cambodia.
Singapore's two losses in October, a 3-1 away friendly defeat to Qatar and a 2-1 defeat against Turkmenistan in an Asian Cup qualifier tie last week, have cost them dearly.
Sundram's side have yet to win since beating Cambodia 1-0 in a pre-Suzuki Cup friendly back in November 2016.
Philippines is the highest-ranked Southeast Asian team in the rankings in 116th.
Despite slipping nine places Iran continue to lead the way overall for the Asian Football Confederation teams, sitting in 34th, ahead of Australia (No.43), Japan (No.44) and China (No.57), who this month moved ahead of South Korea (No.62).