Feb 19 (Reuters) - American Dustin Johnson became golf's world number one for the first time on Sunday with his victory at the PGA Tour's Genesis Open in Los Angeles.
Johnson, who had been third in the world rankings, takes over top spot from Australian Jason Day, who had held the honour for 47 consecutive weeks.
U.S. Open champion Johnson needed to win the tournament and see Day finish worse than a tie for third to claim the number one ranking. He won by five strokes while Day finished in a tie for 64th. (Reporting by Gene Cherry in Salvo, North Carolina; Editing by Peter Rutherford)