Danny Lee carded his second straight 65 and grabbed sole possession of the lead at the inaugural Brasil Classic before Friday's second round was suspended due to darkness.
Following a three-plus hour rain delay, Lee went out with the early wave and picked up eight birdies against a pair of bogeys to reach 12-under 130 through 36 holes.
Overnight co-leader Richard S. Johnson completed 11 holes and reached 10-under before darkness set in at Sao Paulo Golf Club.
Brazilian Philippe Gasnier (68), Dawie van der Walt (66) and Aron Price (65) are 7-under through two rounds, while Sao Paulo's Alexandre Rocha, Tim Wilkinson and Jonathan Hodge are 7-under through eight, 10 and 12 holes, respectively.
Tom Hoge was tied with Lee and Johnson after the first round, but the American shot even-par on Friday to remain at 6-under. Michael Putnam (65) and Kevin Tway (69) also completed their second rounds at 6-under while Benjamin Alvarado is minus-6 through four holes.
Kevin Foley, the only 2013 Web.com Tour winner in the field, will likely miss the cut after carding a first-round 80 and dropping another shot through 13 on Friday to reach 9-over.
After the rain delay, and with the 18th fairway still draining, Lee began his round on the 10th and promptly picked up a birdie. A par/bogey stretch followed, but the 2008 U.S. Amateur champion bounced back with birdies on Nos. 13, 15 and 16.
Lee continued his run around the turn with three birdies in four holes, and rebounded from a bogey on No. 8 with a birdie on his last to establish a 5- stroke lead over the pursuing field.
When Johnson finally teed off, he quickly proved the biggest threat to the clubhouse leader with a birdie on his first hole (the 10th). A winner on the PGA Tour at the 2008 U.S. Bank Championship in Milwaukee, Johnson played bogey-free before darkness set in, adding birdies on Nos. 13, 17 and one to reach 10-under.
Beginning on the 10th tee, van der Walt got off to a strong start with five birdies and an eagle through his first 12 holes. He notched another birdie on the sixth to reach 10-under, but a bogey on the seventh and a double bogey on the ninth dropped the South African five shots off the pace.
NOTES: The second round will resume at 7:30 a.m. (local time) ... Host pro Erik Andersson is 3-under through 36 holes ... Johnson has played in two European Tour events at the Sao Paulo Golf Club. He tied for 11th at the 2000 Brazil 500 Years Open and tied for second at the 2001 Sao Paulo Brazil Open ... Foley won the season-opening Panama Claro Championship. He is currently fourth on the money list and needs at least a second-place finish to take over the top spot from Edward Loar ... Shaun Micheel, the only former major champion in the field (2003 PGA Championship), shot a 70 on Thursday and was even through 12 holes on Friday.