PLAYA DEL CARMEN, Mexico -- Russell Knox and Graeme McDowell each had six birdies and were tied for the lead before the final round was stopped Sunday in the rain-delayed OHL Classic at Mayakoba, setting up a sprint to the finish Monday in Mexico.

The fourth round was delayed 3 1/2 hours by thunderstorms that left pools of water across El Camaleon Golf Club.

McDowell elected to finish the par-5 13th when the horn sounded to suspend play because of darkness. He made birdie to join Knox at 19-under par.

Knox was still on the 13th hole.

Jason Bohn, who chipped in for eagle on the fifth hole for an early lead, dropped two shots and was at 17 under through 12 holes.

OHL CLASSIC AT MAYAKOBA: Leaderboard | Knox looking for back-to-back wins | Projected FedExCup | Travelers Weather Hub

The final round was to resume at 8 a.m. Monday.

This will be the first time in 10 years that back-to-back PGA TOUR events finished on Monday because of rain. The Sanderson Farms Championship in Mississippi had a marathon finish last Monday because of the weather.

With soft conditions, there figures to be little room for error when Mayakoba ends on Monday.

Scott Brown (through 14 holes) and Derek Fathauer (12 holes) were four shots behind. Fathauer, trying to make it six straight PGA TOUR events with a first-time winner, had a one-shot lead starting the final round but had only one birdie against two bogeys to fall back.

Knox is coming off his first win last week in Shanghai at the World Golf Championships-HSBC Champions, and he was so exhausted that he considered pulling out this week. Instead, he continued his around-the-world journey to Mexico. He can become the first player since Camilo Villegas in 2008 to win his first two TOUR titles in successive weeks.

The 30-year-old from Scotland ran off four straight birdies starting at No. 3, and then stuffed his approach just short of the pin on the par-3 eighth and went out in 31. He picked up his sixth birdie on the 11th hole.

Along with three straight birdies on the front nine, McDowell parred the opening hole at El Camaleon. He had played the first in 5 over through three rounds -- two double bogeys and a bogey. This time, he hit 3-wood off the tee.

Justin Leonard, Patrick Rodgers and Freddie Jacobson, and PGA TOUR rookie Harold Varner III were at 13 under, six shots behind.