Lague was 1-under through the first 12 holes, but he holed a bunker shot on No. 13 for birdie to move to 2-under.

"That kind of started it all," Lague said. 

Lague shot a 30 on the back nine, with additional birdies on Holes No. 14, 17, and 18 to get to 5-under.

Jackson Moss of San Diego, Calif., Lague's teammate at San Diego State, is in solo second place after shooting a 4-under 67.

"The greens are really nice, so I was rolling it really well. Just got hot on the front (nine) and stayed steady on the back (nine).

Moss started his round with four pars, then made an eagle on No. 5, a birdie on No. 6, and he also birdied Holes No. 8 and 9 to shoot a 32 on the front nine after a bogey on No. 7.

Trae Cassell of Rancho Sante Fe, Calif., is in solo third place after a round of 2-under 69. He eagled No. 11 and almost holed out his drive on the 328-yard hole that pinches in at 50 yards out. Cassell tapped in a six-inch eagle putt.

"I won't be hitting driver there tomorrow," Cassell said.

Lague now heads into the final round looking to hold off his teammate Moss and the rest of the field.

"I want to hit more fairways," Lague said about the final round. "On the back nine, I hit fairways and hit the green to make birdies. On the front nine, I didn't hit fairways and was scrambling more."

Mark Strickland San Diego, Calif., shot an even-par 71 to lead the Senior Championship Division after the first round. Strickland recorded three birdies and three bogeys. Jim Plotkin of Carlsbad, Calif., and Anthony Ventura of Spring Valley, Calif., are T2 at 1-over and one shot back of Strickland.