Dustin Johnson reclaimed the world number one ranking he lost less than a month ago by winning the FedEx St Jude Classic in Tennessee on Sunday.

The 33-year-old had held top spot for 15 months before fellow American Justin Thomas took it over on May 13.

With Sunday's victory, Johnson will be among the favourites to win the US Open starting on Thursday at the Shinnecock Hills Golf Course in New York.

Johnson mixed three birdies, a bogey and an eagle to finish 19-under-par for his 18th career PGA Tour victory and his second at the St Jude Classic, which he also won in 2012.

The win also moved Johnson into second place in the PGA FedEx Cup rankings behind Thomas.

Seamus Power carded a second successive 70 to sign off on six-under-par. Power slipped down the leaderboard on Saturday after a strong start, but a tied 12th finish represents a good weekend's work for the Waterford man.

Shane Lowry ended the tournament three shots further back as he closed with a 70, while Padraig Harrington shot 71 and finished tied 56th on two-over.