Cape Town - Japan rose to a record high of No 7 in the official World Rugby rankings on Monday.
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This follows their 28-21 win over Scotland in Yokohama on Sunday which saw them qualify for the Rugby World Cup quarter-finals for the first time.
The Brave Blossoms climbed one spot above France and currently also sit higher than Scotland and Argentina in the rankings.
Japan, who earlier also defeated Ireland 19-12, finished top of Pool A and will face South Africa in the last eight.
The Springboks, runners up to the All Blacks in Pool B, remain No 5 in the rankings, behind Ireland, England, Wales and leaders New Zealand.
Top 20 in the latest World Rugby rankings:
1. New Zealand 90.98
2. Wales 88.87
3. England 88.13
4. Ireland 85.93
5. South Africa 85.75
6. Australia 83.52
7. Japan 82.08
8. France 81.38
9. Scotland 79.23
10. Argentina 78.31
11. Fiji 76.21
12. Italy 72.04
13. Tonga 71.44
14. Georgia 71.26
15. Samoa 70.72
16. Spain 68.15
17. USA 68.10
18. Uruguay 67.41
19. Romania 66.69
20. Russia 63.09
Others:
23. Namibia 61.01
32. Kenya 52.55
34. Zimbabwe 50.69
RWC quarter-finals fixtures (all times SA):
Saturday, October 19:
England v Australia, Oita - 09:15
New Zealand v Ireland, Tokyo - 12:15
Sunday, October 20
Wales v France, Oita - 09:15
Japan v South Africa, Tokyo - 12:15