Dustin Johnson says he's not sure how he became world number one

As of last weekend, 19 players had reached the top since the world ranking system was introduced at the 1986 Masters. Six of them were at the Genesis Open course in Riviera (California), including the then number one player, Jason Day, who had led the world ranking for 47 consecutive weeks.

Not anymore. The new world number one is 32-year-old South Carolina-born Dustin Johnson, the reigning U.S. Open champion, who dominated the last PGA Tour tournament , winning it with a five-stroke lead.

This win has propelled him to the top spot in the rankings, something that even for him was a surprise. “I don’t really understand it,” Johnson said of the world ranking scoring system, “but I can read 1, 2, 3, and I guess that’s all that matters.”

Winning tournaments is also what matters, and Johnson has proven he knows the formula. This was the thirteenth victory of his career, and he has won at least once in each of his ten seasons on the American Tour. Only three other players have achieved that feat of winning consistency: Arnold Palmer, Jack Nicklaus and Tiger Woods.

The 20 world number ones (in order since 1986) are as follows:

Bernhard Langer

Severiano Ballesteros

Greg Norman

Nick Faldo

Ian Woosnam

Fred Couples

Nick Price

Tom Lehman

Tiger Woods

Ernie Els

David Duval