Emiliano Grillo's birdie blitz vaulted the Argentine to a four stroke lead heading into the weekend at the Mayakoba Classic in Playa del Carmen, Mexico.
The 29-year-old nailed nine birdies and one bogey for a round of 63 on a soggy day at the El Camaleon Golf Club. He is 13-under par for the tournament, where he is looking to claim his second win on the PGA Tour.
"Everything worked today," Grillo said.
"I played from the fairway, hit it close and when it wasn't too close, I made putts. It was one of those days," he said.
"I did my work the first two days. I've just got to keep it up for another two days and I'm pretty sure I will get it done."
Lurking four strokes back are Americans Tony Finau (66) and Tom Hoge (67) with overnight leader Russell Knox (69) of Scotland one further adrift.
Finau, who missed two tournaments in October due to a nasty case of Covid-19, said he is eager to claim his second PGA Tour victory but said this year has taught him that there are limits to what he can control.
"I think we've all learned a lot of patience this year, me included, with Covid and everything," he said.
"I learned this game doesn't owe you anything, you've got to earn everything you have, earn all your wins. It's been a long time coming I feel like for number two. Hopefully it happens here in a couple days."
Friday's round was called for darkness and a handful of players will have to finish their second rounds on Saturday morning.
Four-time major winner Brooks Koepka, 2019 US Open champion Gary Woodland and five-time PGA Tour event winner Rickie Fowler were among those in danger of missing the cut.
Graeme McDowell carded a 71 to finish on one over after two rounds, outside the projected mark which is at level par.