Paris - As the US Open gets underway at Flushing Meadows the ATP rankings reveal just two American men in their world top twenty, 11th placed John Isner and in 18th Jack Sock.
The pair are both in action on the opening day with Sock facing Argentine Guido Andreozzi and Isner tackling compatriot Bradley Klahn.
Atop the rankings are the veteran rivals defending US Open champion Rafael Nadal and the Swiss master Roger Federer in 2nd.
The 2017 US Open champion Stan Wawrinka is out of the top 20 as is 2012 champion Andy Murray, who is coming back from hip surgery.
1. Rafael Nadal (ESP) 10 040 pts
2. Roger Federer (SUI) 7 080
3. Juan Martn Del Potro (ARG) 5 500
4. Alexander Zverev (GER) 4 845
5. Kevin Anderson (RSA) 4 615
6. Novak Djokovic (SRB) 4 445
7. Marin Cilic (CRO) 4 445
8. Grigor Dimitrov (BUL) 3 790
9. Dominic Thiem (AUT) 3 485
10. David Goffin (BEL) 3 435
11. John Isner (USA) 3 200
12. Pablo Carreno (ESP) 2 425
13. Diego Schwartzman (ARG) 2 380
14. Fabio Fognini (ITA) 2 190
15. Stefanos Tsitsipas (GRE) 2 042
16. Kyle Edmund (GBR) 1 935
17. Lucas Pouille (FRA) 1 915
18. Jack Sock (USA) 1 815
19. Kei Nishikori (JPN) 1 755 (+2)
20. Borna Coric (CRO) 1 735