The 40-year-old American, who has not won a title since the 2014 RBC Heritage, finished the third round on 20 under, a 54-hole aggregate of 193.

Kuchar, who had moved two strokes clear of the field on Friday after a second straight 64, barely put a foot wrong once more on the El Camaleon Golf Club Course at Playa del Carmen.

The world number 40 made four birdies and five pars to reach the turn at four under for the day, and then grabbed two more birdies on the 12th and 13th.

A bogey on the par-four 14th after a wayward tee-shot gave the chasing pack a glimmer of hope, but Kuchar duly hit back on the 15th with his seventh birdie of the day to restore his four-shot cushion.

South Korea's Kim Whee will lead the pursuit of Kuchar on Sunday after shooting a five-under-par 66 to move to 16 under, four off the pace.

The 26-year-old from Seoul, who is yet to record a victory on the PGA Tour, carded four birdies on the front nine before claiming a fifth of the day on the 15th.

But there was disappointment for 23-year-old Cameron Champ, who was on course to finish the third round tied for second with Kim only for a double-bogey six on the 18th to send him sliding down the leaderboard.

Champ's double on the last left him at 14 under, six strokes back from Kuchar, heading into the final round.

With Kim four off the lead, Richy Werenski and New Zealand's Danny Lee are five adrift on 15 under. Werenski and Lee both made 67 to stay in touch.

The low round of the day belonged to Aaron Wise, who lit up the course with an eight-under-par 63.

The South African-born 22-year-old from California, who bagged a maiden PGA Tour win last season at the AT&T Byron Nelson, played flawlessly to register eight birdies and no pars.

Wise heads into Sunday six shots off the lead alongside J.J. Spaun and Champ on 14 under.