The World Number One, who won the inaugural event here two years ago before finishing as runner-up to Graeme McDowell 12 months later, carded a closing 68 at Royal Greens Golf and Country club to finish on 15 under par.

That was two clear of Finau and Justin Rose as the American overcame a cold putter to capture his ninth European Tour title.

“Conditions when we started were really tough,” Johnson said.

“I knew I was hitting it well, I saw the leaderboard and I knew the guys were playing well.

“I kept giving myself chances - I didn’t hole any of them but I hit good shots and I finally holed a really nice putt on 13 and from there on I played solid.”

Johnson’s victory strengthens his position at the top of the Official World Golf Ranking and he added: “Couldn’t hole any putts today. Just the reads, I’d see it going left to right it would go right to left; I’d see it going right to left it would go left to right. It was tough all day today.

“I don’t get to play around the world as much as I’d like to and its definitely nice to get a win not on my tour.

“After Augusta to get my first win, the game’s still in really good form and I’m looking forward to the rest of the year.”

European Tour