Slattery overcame windy conditions at the El Encin Golf Hotel for a 6-under-par 66 Friday. He is 11-under 133 for the tournament.
Eduardo De La Riva and Francisco Molinari each shot 5-under 67 Friday and share second one stroke behind Slattery. Lorenzo Gagli had a 2-under 70 in the second round and is alone in third at 9-under 135.
Slattery opened with a birdie at the first hole and used birdies at 6 and 8 to make the turn at 3-under. He added a birdie at the 10th hole but had a bogey at No. 12. He got that stroke back at 14 -- dropping in an 80-footer for birdie -- but it was birdies at 17 and 18 that put him in the lead.
"I got off to a good start," Slattery said. "I was 2-under early and just kept it together and had a nice finish, birdied the last two holes," he said.