Justin Thomas poses with the trophy after winning the CJ Cup on Jeju Island, South Korea on Sunday. Photo: Park Ji-ho/Yonhap via AP

PARIS – American Justin Thomas moved to a career-high world ranking of third on Monday after claiming his fifth title of the year at the inaugural CJ Cup in South Korea.

The 24-year-old beat Australian Marc Leishman, who also climbed to a career-best of 12th, in a playoff to continue an incredible run of form that has also seen him win the PGA Championship and the FedEx Cup.

Spaniard Sergio Garcia retook his place in the top 10 after winning his first title since breaking his major duck at the Masters in April at his own tournament at Valderrama.

The top three players in the world are now all American, with Thomas closing in on Open Championship winner Jordan Spieth and World No 1 Dustin Johnson.

The last time that was the case was in May 2010, when Tiger Woods, Phil Mickelson and Steve Stricker were the leading trio.

World Top 20

1. Dustin Johnson (USA) 11.46 average points

2. Jordan Spieth (USA) 10.15

3. Justin Thomas (USA) 9.23 (+1)

4. Hideki Matsuyama (JPN) 8.82 (-1)

5. Jon Rahm (ESP) 7.65

6. Rory McIlroy (NIR) 6.58

7. Rickie Fowler (USA) 6.31

8. Jason Day (AUS) 6.23 (+1)

9. Henrik Stenson (SWE) 6.14 (-1)

10. Sergio Garcia (ESP) 6.11 (+1)

11. Brooks Koepka (USA) 6.06 (-1)

12. Marc Leishman (AUS) 5.56 (+4)

13. Justin Rose (ENG) 5.46

14. Matt Kuchar (USA) 5.38 (-1)

15. Paul Casey (ENG) 5.22 (-1)

16. Alex Noren (SWE) 5.02 (-1)

17. Tyrrell Hatton (ENG) 4.79

18. Pat Perez (USA) 4.54 (+2)

19. Tommy Fleetwood (ENG) 4.41 (-1)

20. Francesco Molinari (ITA) 4.33 (-1)