South Korea, which recently qualified for the 2018 FIFA World Cup, has dropped out of the top 50 in the latest world rankings from the world football governing body.

According to the September rankings unveiled by FIFA on Thursday, South Korea fell two spots to No. 51, having accumulated 659 points. The country trails three other Asian Football Confederation members: Iran (23rd), Japan (40th) and Australia (50th).

South Korea began 2017 at No. 37, but its ranking has gradually fallen over the year. 

The Taeguk Warriors have earned their spot at the 2018 FIFA World Cup after finishing second in the final Asian qualifying round. However, their last two qualifying matches -- against Iran on Aug. 31 and Uzbekistan on Sept. 5 -- ended in scoreless draws.

South Korea will play two friendly matches before the next FIFA rankings are released Oct. 14. The men's national football team, led by head coach Shin Tae-yong, will first take on No. 64 team Russia in Moscow on Oct. 7, and they will face Tunisia, who are No. 31, three days later in Cannes, France.

Meanwhile, Germany returned to the top position after pushing Brazil to No. 2. Portugal was third after moving up three spots, followed by Argentina and Belgium.

FIFA rankings are based on the average number of points that a team accumulates over a four-year period. The ranking points in each match are determined by its result, its value, and the relative strength of the opponent and their confederation. The system also has a yearly basis depreciation for the value of the matches. (Yonhap)