Day finished as a runner-up for the third time in a major championship at the 2013 U.S. Open at Merion Golf Club. He finished in a tie for second alongside Phil Mickelson, two strokes behind Justin Rose. Day tied the lead with a birdie at the 10th, but bogeys at 11, 14, and 18 would prevent him from winning his first major championship. It was the second time in his career Day had finished as a runner-up at the U.S. Open, and Day is also the only player in 2013 to hold a lead on the back nine Sunday at both majors. He tied for the lowest cumulative score in all four majors in 2013, with fellow Australian Adam Scott at +2.