Jordan Spieth says it "bothers" him that Jason Day is increasing his lead at the top of the world rankings.
Day's victory at the Players Championship last week was his seventh in his last 17 events, a run which includes his record-breaking major breakthrough at the PGA Championship at Whistling Straits.
Such form has taken Day from 10th in the rankings in June last year to 2.5 points clear of Spieth, with Rory McIlroy a further two points adrift, a marked contrast to the period last season when the top spot changed hands seven times in 12 weeks.