LOS ANGELES • Dustin Johnson said that he could not be happier with his form after he reclaimed golf's world No. 1 ranking with a six-shot victory at the St Jude Classic on Sunday.

The win is also the perfect warm-up for the American as he aims to clinch a second US Open title this week following his victory at Oakmont in 2016.

"I have high expectations going in every week," Johnson said. "But I feel like my game's in good shape.

"I'm driving really well. I'm hitting my irons well, and my wedges are really good. I'm really looking forward to it.

"I haven't seen the golf course (Shinnecock Hills Golf Course in New York for the US Open) yet but I'll go there tomorrow and get 18 holes in and we'll see."

Johnson, who started the day alongside Andrew Putnam at the top, held his nerve to close with a four-under 66 at TPC Southwind in Memphis, Tennessee.

The 33-year-old sealed his win in emphatic style, mixing three birdies and a bogey before holing out for a sensational eagle on the 18th to roars from the gallery.

He finished the tournament on a 19-under total of 261, while Putnam carded a 72 to finish on 267.

It was Johnson's 18th career PGA Tour victory and his second at the St Jude Classic, which he also won in 2012.

"What a cool way to end the day to hole that shot on 18," added Johnson, who notched his first win since a triumph at the Sentry Tournament of Champions in January.

"It was nice to be back in the hunt, to get the lead and to get the juices flowing a little bit.

"It feels like it's been a long time (since my last win), even though it's been only six months.

"A lot of good things happened this week. I knew coming in this week I was swinging really well and I had confidence in my game."

Johnson had ceded his No. 1 spot to Justin Thomas last month following a 64-week reign.

But the win ensures he will return to the top of the rankings as the golf world prepares for the second Major of the season.

AGENCE FRANCE-PRESSE, REUTERS