Rory McIlroy had more trouble with his stomach than his ribs. He opened with a 3-under 68 and was one shot out of a six-way tie for the lead as the Mexico Championship made a strong debut Thursday.
Phil Mickelson and Lee Westwood, two of the four players who were in the field for the first edition of this World Golf Championships event 18 years ago, each shot 67 and were part of a big group atop the leaderboard at Chapultepec Golf Club that included PGA champion Jimmy Walker, Torrey Pines winner Jon Rahm and Ryan Moore.
Westwood and Walker each bogeyed their last two holes.
McIlroy, who can go to No. 1 with a victory, was playing for the first time since Jan. 15 because of a rib injury.