Russell Knox and Andrew Putnam have finished day two at the Shriners Hospitals for Children Open with a share of the lead on 10-under-par.
Scotland's Knox recovered from a sluggish start after carding bogeys on two and three to shoot a second-round 67 at TPC Summerlin in Las Vegas.
Putnam also scored a bogey on three but it proved the only blemish in a round comprising of seven birdies and 10 pars as the American shot 65.
Andrew Svoboda and Tony Finau are a stroke behind on nine-under, while Spencer Levin and George McNeill came from nowhere to give themselves a chance heading into the weekend.
The duo began the round on even par but sit just two shots adrift of the co-leaders after both registered an impressive 63 to begin Saturday on eight-under.
Levin's hopes of improving on his first-round 71 looked grim when the American scored bogeys on three and five, yet the 30-year-old hit back with seven birdies in the back nine.
There are six other players also on eight-under - Martin Laird, Wes Roach, Scott Piercy, Bo Van Pelt, Ben Martin and Webb Simpson.
Shane Callaghan
