Riley leads at halfway in Charles Schwab Challenge

American Davis Riley holds a two-shot halfway lead at the Charles Schwab Challenge in Texas.

Riley endured a 70-minute wait due to thunderstorms in the area during his bogey-free second round, backing up his strong start to the tournament with a six-under-par 64 on Friday.

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.