Taylor Fritz has become the first American in almost five years to be ranked in the ATP men's top 10 due to his win in the Japan Open.
The 24-year-old rose three places to eighth in the rankings released on Monday following his victory over compatriot Frances Tiafoe.
Jack Sock was the last American to break into the top 10 in November 2017.
Tiafoe's consolation for losing to Fritz is his highest ever ranking of 17th.
Spain's US Open champion Carlos Alcaraz retains top spot despite losing in the first round in Astana last week.
His compatriot Rafael Nadal stays second after a week in which the 36-year-old had something else to celebrate, the birth of a baby boy.
Nadal's great rival Novak Djokovic won the 90th title of his career in Astana on Sunday but remains in seventh spot in the rankings.
Stefanos Tsitsipas, who lost to Djokovic in the final, still moves up one place to fifth at the expense of the injured Alexander Zverev.
1. Carlos Alcaraz (ESP) 6740 pts
2. Rafael Nadal (ESP) 5810
3. Casper Ruud (NOR) 5645
4. Daniil Medvedev 5245
5. Stefanos Tsitsipas (GRE) 5065 (+1)
6. Alexander Zverev (GER) 5040 (-1)
7. Novak Djokovic (SRB) 4320
8. Taylor Fritz (USA) 3510 (+3)
9. Andrey Rublev 3480
10. Cameron Norrie (GBR) 3445 (-2)
11. Hubert Hurkacz (POL) 3265 (-1)
12. Jannik Sinner (ITA) 3040
13. Felix Auger-Aliassime (CAN) 2950
14. Marin Cilic (CRO) 2540
15. Pablo Carreno (ESP) 2360
16. Matteo Berrettini (ITA) 2360
17. Frances Tiafoe (USA) 2240 (+2)
18. Diego Schwartzman (ARG) 2110 (-1)
19. Karen Khachanov 2035 (-1)
20. Denis Shapovalov (CAN) 1925 (+2)