Russell Knox sunk six birdies in 11 holes and was tied with Graeme McDowell when the fourth round of the rain-delayed OHL Classic at Mayakoba was stopped on Sunday.
McDowell birdied the par-5 13th before it was too dark to continue. Knox was on the 13th hole.
They were at 19-under par.
It will be the second straight week that a PGA Tour event went to Monday because of rain. That hasn't happened in 10 years.
Knox won the HSBC Champions last week in Shanghai. He can become the first player since Camilo Villegas in 2008 to win his first two PGA Tour titles in successive weeks.
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Jason Bohn was at 17 under through 12 holes.
Derek Fathauer, the 54-hole leader, was one over for the day and four shots back.
Aaron Baddeley shot an even-par 71 in the final round for a five-under 279 total, 14 behind the leaders while Robert Allenby was on two-under but was yet to complete his round.
