World Golf Championships-Mexico Championship: Collected his first top-10 of the season with a T10 at the World Golf Championships-Mexico Championship. Marked his 13th career top-10 finish in the event and 34th in World Golf Championships events. Second-round 66 at Club de Golf Chapultepec highlighted his competitive debut in Mexico. Four-putted the par-5 15th green and three-putted the par-4 16th green in the third round, marking the first time in his career he had four-putted and three-putted in back-to-back holes, a stretch of 22,640 holes in stroke-play events before reaching the par-5 15th in the third round.
U.S. Open Championship: Earned his eighth major championship, with the sixth wire-to-wire victory in U.S. Open history. Win was his seventh in his last 11 major championship appearances. Finished 3-under and won by three strokes over runner-up Phil Mickelson, the only other player to finish at par or better for the championship. Tied Tom Watson for fifth all time, with eight professional major victories. Became the fifth player to win the first two majors of the season, joining Craig Wood (1941), Ben Hogan (1951 and 1953), Palmer (1960) and Nicklaus (1972). In receiving the $1-million paycheck, became the first player to surpass the $30-million mark in career earnings and the first to exceed $4 million in four consecutive seasons.
Surgery: Pulled out of next two PGA TOUR starts, the Genesis Open and The Honda Classic. Released statement: "My doctors have advised me not to play the next two weeks, to continue my treatment and to let my back calm down. This is not what I was hoping for or expecting. I am extremely disappointed to miss the Genesis Open, a tournament that benefits my foundation, and The Honda Classic, my hometown event. I would like to thank Genesis for their support, and I know we will have an outstanding week." In April, announced on his website he had undergone further back surgery. The operation was performed by Dr. Richard Guyer of the Center for Disc Replacement at the Texas Back Institute.