March 4 (Reuters) - A hole-in-one boosted Justin Thomas to a one-stroke lead over fellow American Dustin Johnson, and a two-shot cushion over Phil Mickelson and Rory McIlroy after the third round at the WGC-Mexico Championship in Mexico City on Saturday.
American Thomas took over thanks in no small measure to his ace at the par-three 13th, where his six-iron from 232 yards took a big hop and disappeared into the cup on the second bounce.
The world number eight carded 66 for 12-under-par 201 with one round left.
Johnson found his putting touch to also card 66, while American compatriot Mickelson overcame some poor driving and used a couple of fortunate breaks to shoot 68, with Northern Irishman McIlroy firing a solid 70. (Reporting by Andrew Both in Cary, North Carolina, editing by Gene Cherry)