Davis Riley leads Charles Schwab Challenge by two shots amid weather delays

Riley endured a 70-minute wait due to thunderstorms in the area as he faced a par putt on his final hole on Friday but managed to sink it and back up his strong start to the tournament with a six-under-par 64.

"Luckily, it was a three-footer straight up the hill, so (there) wasn't too much to stress about," Riley said. "I knocked in about five three-footers before walking over there to cap off the round -- hit it center cut and made it.

"It was nice to finish the day and made for a good, pretty stress-free six-under."

The 27-year-old has won just once on the PGA Tour but never on his own — his only success coming in the Zurich Classic team event with Nick Hardy last year.

Two shots behind are fellow Americans Hayden Buckley and Pierceson Coody, while Sungjae Im hit a 64 to move within four shots of the lead.

Austria's Sepp Straka, who made his debut in the Ryder Cup last year, had an up-and-down day with six birdies and two bogeys to finish in a group tied for fourth alongside the South Korean.

World number one Scottie Scheffler fought back from his worst opening round of the season with a five-under-par 65 to sit seven shots off the lead.

He hit four straight birdies around the turn in his faultless round.