Charley Hoffman had a 2-under 70 for a one-shot lead over Jamie Lovemark at the Houston Open on Friday.
Lovemark was a former NCAA champion seeking his first PGA Tour title after having his career affected by back surgery. He was one of four players to shoot the day's low score, 68, under conditions that worsened as the afternoon went on, which helped protect Hoffman from the field.
Dustin Johnson was among those chasing Hoffman, who opened with a 64 Thursday, but Johnson dropped back to 8 under with a bogey on 17, closing with a 71 after narrowly missing a 10-foot birdie putt on 18.
Johnson was in the last group to finish the round before darkness stopped play.
A 93-minute morning weather delay brought on by rain and lightning in the area ensured that 27 players will have to complete the second round Saturday morning.