Merritt, who also had an eagle on the par-five second and four birdies on the back nine, had 18 points total in his round and sits two points clear of fellow American Robert Streb at the event played under the modified Stableford format.

The format, which is designed to reward aggressive play, gives eight points for an albatross, five for eagle, two for birdie, zero for par and subtracts a point for bogey and three for double-bogeys or worse.

Promising Tour rookie Collin Morikawa was in third with 33 points.

Merritt said keeping his putter hot will be key as the 33-year-old looks to capture his third PGA Tour victory.

"The last couple weeks the putter was ice cold but we've putted really well this week," he said.

"Read the greens well, speed has been really good. We had two three putts but usually when you're putting well you're being aggressive and you're going to have a couple mistakes.

"That just needs to keep up tomorrow, need to keep making putts."

Merritt's march to the top of the leaderboard in Nevada comes a year after he first began experiencing arm pain that was later revealed to be a 12-inch blood clot that ran from his elbow to his chest.

Doctors successfully removed the clot in August.

The rain and lightning that forced delays during the first two rounds at the Montreux Golf & Country Club gave way to brilliant sunshine on Saturday, where the high elevation and receptive greens made for excellent scoring conditions.