Australia's 3-2 aggregate win over Syria set up a final two-leg intercontinental play-off in November against 69th ranked Honduras for a place at Russia 2018.
The Socceroos latest ranking sees them overtake Japan (44th) as the second-highest team from the Asian confederation, with Iran at 34th.
It is the highest ranking Ange Postecoglou's side have achieved this year, after falling to 50th in September, and has laid the platform for an unprecedented third pot seeding at the 2018 World Cup.
With the World Cup seedings being based on the October rankings, it is possible that if the Socceroos qualify - they could scrape into the top 24 nations for Russia 2018.
At previous World Cups, Australia have been rated as one of the bottom eight sides, leading to difficult draws.
None have been more taxing than Spain, the Netherlands and Chile at the 2014 tournament.
Four teams that have already qualified for Russia - Japan, South Korea, Saudi Arabia and Panama - are ranked lower than Australia.
With nine places yet to be filled, if four of those countries are also ranked below the Socceroos, Australia would be bumped into pot three for the draw - to take place in December.
Eight teams ranked below Australia remain in contention - including world number New Zealand.
Meanwhile, world champions Germany continue to top rankings - a position the country has held since last month.
Germany, Brazil, Portugal, Argentina, Belgium, Poland and France join hosts Russia, the world number 65, as seeded teams for the global showpiece.
Heavyweights Spain and England have missed out on the crucial top seeding and will enter the tournament from pot two.
Peru are into the top 10 for the first time, climbing two places to 10th ahead of their intercontinental play-off against the Kiwis.
FIFA WORLD RANKINGS