Webb Simpson was challenged by his house guest Nick Watney on day two of the Wells Fargo Championship.
While Watney, who is staying at Simpson's house near Quail Hollow for the tournament, hit an eight-under-par 64 to lead his host by a stroke on 12 under overall, Tiger Woods missed the cut for just the eighth time in his career.
It means Simpson, who went into Friday's round as part of a three-man leading group, and Watney will play together on Saturday while Woods heads home.
"It'll be fun to go out with my room-mate," Simpson said on www.pgatour.com.
Behind Simpson was a group of four players on 10 under in another of the overnight leader Stewart Cink, DA Points, John Senden and Ben Crane, who like Watney carded a 64.
The third of the overnight leaders, Ryan Moore, was on his own in seventh on nine under after shooting a 70.
Watney birdied seven of the first 12 holes and, after dropping a shot at 13, stormed back with an eagle at the par-five 15th.
Watney said: "I've worked really hard these five days leading into this event. I think it just shows I'm making progress.
"Who knows what's going to happen this weekend, but I'm really excited for it."
Simpson, meanwhile, passed up a chance to lead alongside Watney when he bogeyed his last hole, the ninth.
Woods departed after a 73 left him level for his first two rounds, missing the one-under cut.
Woods said: "This is one of my favourite Tour stops, and unfortunately, I'm just not going to be around for the last two days."
Lee Westwood and Phil Mickelson both recorded 72s to edge their way into the weekend on one under, while Northern Ireland's Rory McIlroy launched his challenge in earnest with a 68 which put him in a share of 13th on six under.
Scotland's Martin Laird also made it to Saturday as his 71 left him two under, but defending champion Lucas Glover bowed out with a 76.