Matt Kuchar edged past clubhouse leaders Webb Simpson and Gary Woodland on Friday as darkness halted play in the weather-disrupted Barclays, the first event in the US PGA Tour playoffs.
Kuchar had five birdies and no bogeys through 13 holes of his second round and was 10-under for the tournament when play was suspended.
He'll return on Saturday morning to try to seal the 36-hole lead.
Former US Open champion Simpson had made a marathon day look easy, firing a second-round 66 to take the early clubhouse lead on nine-under 133.
He was joined late in the day by Woodland, who notched a sparkling 64 that included eight birdies and a bogey.
"When you're playing well, you feel like you could play 40 holes in a day," said Simpson, who in fact played 29 -- first finishing up his first round after weather delays totalling almost six hours on Thursday.
Simpson and Woodland were two strokes clear of their nearest rivals in the clubhouse.
Masters champion Adam Scott, Rickie Fowler and Keegan Bradley were all in on seven-under 135, while England's Justin Rose, the reigning US Open champion, was at seven-under for the tournament through 14 holes.
Fowler set a Liberty National Golf Club course record with a 64, only for Bradley to break it with a 63 -- all before Woodland completed his own 64.
Scott carded a 66. The Australian, who hasn't won since capturing his first major title at Augusta National in April, was also happy to put in a long day. He played 12 holes of his first round before completing his second.
"I'm pretty happy with today's effort," Scott said. "When we went out this morning, the wind was up, and the course played a lot tougher than the few holes I played yesterday."
Nevertheless, he had an eagle, a birdie and one bogey over his 12 holes to conclude the first round, and added five birdies and another eagle in the second.
"Playing 30 holes in a day is good -- if you're playing well," Scott said.
He played in a group with Bradley, whose course-record 63 included eight birdies without a bogey. Fowler had six birdies and an eagle and one bogey in his 64.
Among those who were unable to finish, Northern Ireland's Rory McIlroy had seven birdies and two bogeys through 16 holes to stand at five-under for the tournament and world number one Tiger Woods was one-under for the day and five-under for the tournament through 13 holes.
Woods came into the $8 million tournament topping the playoff standings thanks to five US PGA Tour wins this season.
The top 125 players in the standings qualified for this week's field. Only 100 will go on to the Deutsche Bank Championship in Boston. Seventy will then play the BMW Championship in Chicago, with the top 30 on the points list qualifying for the Tour Championship in Atlanta.
The player topping the standings after the four events wins a $10 million playoff bonus.