Hole-in-one helps Thomas lead Johnson at WGC-Mexico

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A thrilling conclusion is in prospect at the WGC-Mexico Championship after Justin Thomas moved to the top of a star-studded leaderboard on Saturday.

Thomas, already a three-time winner on the PGA Tour this season, stormed ahead of the pack by shooting a five-under 66 for the second day in succession to reach 12 under.

However,  Dustin Johnson is only one back, a stunning eagle at the first helping the world number one to match Thomas' third-round score, while Rory McIlroy (70) and Phil Mickelson (68) are a further stroke behind in a share of third.

Thomas' round was highlighted by an eye-catching hole-in-one at the par-three 13th. The ball took one big hop and landed right in the cup.

There were also four back-nine birdies for Thomas, enabling him to overhaul Johnson, who had led for much of the day.

Johnson enjoyed a wonderful start to round three. After beginning the day three behind McIlroy, he drove the 322-yard first hole with a two-iron to set up an eagle before birdieing the second and sixth to claim sole possession of the lead.

Further gains came the way of Johnson on the 13th and 15th, before a bogey on 16 prevented him from sharing the lead overnight.

McIlroy, playing his first event since January following a rib injury, could not replicate his Friday form but remains handily placed, while Mickelson birdied the 15th, 16th and 17th to boost his hopes, only to drop a shot at the last.

Lee Westwood (66) and Jon Rahm (67) are also in contention at nine under, with fellow Europeans Tommy Fleetwood (66), Thomas Pieters (68) and Tyrrell Hatton (68) are four off the pace.

Jordan Spieth made a big impact early on Saturday with a tournament-low eight-under 63. Spieth had six birdies and an eagle to get back within shouting distance of the leaders, but will likely require a similar round on Sunday to win.