LOS ANGELES (AP) -- One of Jason Day's goals at the start of the year was to stay at No. 1 for the entire calendar year. The year is not even two months old, and already he is facing his first big challenge.
And not just from one player.
Dustin Johnson, coming off a third-place finish at Pebble Beach, and Phoenix Open champion Hideki Matsuyama both have a mathematical chance to reach No. 1 in the world by winning the Genesis Open at Riviera. Johnson would need Day to finish around fourth or worse, while Matsuyama could reach the top only by winning and Day finishing about 25th or worse.