Russell Henley carded the lowest 54-hole score of the season to pull six strokes clear at the final turn at the World Wide Technology Championship at Mayakoba on Saturday.
The 33-year-old American carded a six-under-par 65, following on from successive rounds of 63 to hold a significant advantage from the nearest contenders, Will Gordon and Patton Kizzire at 16 under. Henley has tallied 191 across the three rounds at El Camaleon Golf Club.
Only four players had a better third round than Henley, who went into the day's play with a three-shot lead. Henley's long putt for birdie on the par-three 15th hole was his 22nd birdie of the tournament.
Seamus Power, who won last week's Butterfield Bermuda Championship, enjoyed the round of the day with an eight-under 63 to be alone in third.
Power's round included four birdies and two eagles, with one of the latter being a 138-yard hole-in-one on the eighth.
The Irishman is behind Gordon and Kizzire at 15 under, with Troy Merritt and Brian Harman one shot behind at 14 under. Reigning back-to-back champion Viktor Hovland is a further stroke behind among a group of four players.
Greyson Sigg, who is 13-under overall, aced the 10th to join Power and make it two holes-in-one on the same day in excellent conditions.
Joel Dahmen went within a whisker of the second-ever hole-in-one on a par four in PGA Tour history, when his massive approach landed inches away from the flag on the 17th hole.