First-round co-leader Jordan Spieth followed his 63 with a second-round 66 on Friday to reach 11 under and take a 1-shot lead over Jason Kokrak at the Charles Schwab Challenge in Fort Worth, Texas.
Play was suspended due to inclement weather but resumed a couple of hours later.
Spieth completed his first two rounds without a bogey or worse, but he had to work to save par on the final hole at Colonial Country Club.
After a bad swing on his approach, Spieth had to sink a 16-foot putt from the fringe.
"I told Michael even before that hole started, I was starting to lose focusand was kind of just making swings, going through the motions and kind of notreally as sharp the last three or four holes," Spieth said.
"And sure enough, right after that, I bladed a sand wedge, which I don't think I've ever done in competition. And luckily that one went in to really not kind of hurt me there, and ... dinner will taste a little better."
The Texan was generally happy with his long day.
"I came out of the rain delay and I made a nice putt on 3, and really felt like I had a chance to birdie almost every hole on that front nine and even into the back nine," he said. "But I wasn't -- I didn't swing it as well. I wasn't really completing it and it wasn't feeling great. I knew I was going to kind of have to manage my way around the golf course a little bit, and fortunately did a really great job of that. It's nice if you play a bogey-free round."
Kokrak shot a second consecutive 65, carding six birdies and one bogey.
"I'm happy with the way I'm hitting the ball," Kokrak said. "I'm getting a little bit more comfortable on the greens and just giving myself as many opportunities as I can."
Kokrak finished in a tie for third at the event last year when Daniel Berger defeated Collin Morikawa in a playoff.
Colombia's Sebastian Munoz (65 on Friday), Spain's Sergio Garcia (69) and American Patton Kizzire were tied for third, three shots back of Spieth.
Maverick McNealy (63), Charley Hoffman (62), Erik Compton (68) and Adam Hadwin (67) finished at 7-under 133.
PGA champion and two-time winner of the Schwab tournament Phil Mickelson missed the cut when he failed to hit a 10-foot putt on 18.
"I love this tournament and am sad I won't be here for two more days," sad Mickelson, who will take the next couple of weeks off to prepare for the U.S.Open at his hometown Torrey Pines Golf Club in San Diego.