Kuchar was at 10-under par with five holes remaining and had to return Saturday morning to hold his one-shot lead over Webb Simpson and Gary Woodland, who both finished the second round in the rain-delayed tournament.
Simpson had to play 29 holes 11 holes to finish his first round in the morning, followed by his second round and he was ready to go more. He ran off six birdies over an eight-hole stretch and had a 5-under 66.
"It's much nicer when you're playing well to keep playing. And when you're playing well, you feel like you could play 40 holes in a day," Simpson said. "My main goal ... I just wanted to get done today. It just felt nice to putt out on 9, knowing that I've got tonight to sleep and catch up on rest."
Woodland was one of the last players to finish at twilight Friday, and he finished strong. Woodland, back on track after a win at the Reno-Tahoe Open three weeks ago, birdied four of his last five holes for a 64 to join Simpson in the clubhouse at 9-under 133.
In Snoqualmie, Wash., Bart Bryant got off to a fast start in his bid to win consecutive Champions Tour titles, shooting a 6-under 66 to take the first-round lead in the Boeing Classic. Bryant had eight birdies and two bogeys at TPC Snoqualmie Ridge, five days after winning the Dick's Sporting Goods Open winner in Endicott, N.Y., for his first victory in his rookie season on the 50-and-over tour.
Duffy Waldorf and Bobby Clampett shot 67, and Bernhard Langer, Dick Mast and Kirk Triplett followed at 68.
In Edmonton, Alberta, top-ranked Inbee Park shot a 5-under 65 for a share of the second-round lead with playing partner Cristie Kerr in the Canadian Women's Open. Park had seven birdies and two bogeys at Royal Mayfair to match Kerr at 8-under 132.
Matt Kuchar -10
Webb Simpson -9
Gary Woodland -9
Four tied -7
Tiger Woods -5
Daniel Summerhays -3