Davis, an Englishman who is a member of the European Tour, posted a 3-under 69, while Rashell carded a 5-under 67. They are knotted at 15-under-par 273.
The tournament is a 108-hole event marathon, and after its completion, the top 30 players earn full exempt status on the PGA Tour in 2005. Players who finish out of the top 30 but in the top 80 will receive full exempt status on the Nationwide Tour in 2005, while the remaining players will be non-exempt members on that tour.
Play is split over the Jack Nicklaus Tournament Course and the PGA West Stadium Course over the six rounds.
Brehaut played on the PGA West Stadium Course on Saturday and did not get off to a spectacular start. He bogeyed the par-5 fifth, but reclaimed the lost stroke at the next par-5, the eighth. Brehaut dropped a shot at nine to make the turn at 1-over-par 37.
Brehaut, who has partial PGA Tour status for 2005 after finishing 149th on the money list in 2004, drained a 10-footer for birdie at the 10th to get back to 16 under par. He bogeyed 13, but came back to birdie the next. Brehaut bogeyed another par-5, the 16th, but birdied No. 18 to take his one-shot advantage with two rounds to play.
'Perseverance is the key,' said Brehaut, the Q-School medalist in 2002. 'If you've been here as many times as I have been you tend to figure it out. I've putted really well this week. If I continue to putt like I've been putting the last month then I'll be fine out there on the PGA Tour.'
Davis mixed four birdies and two bogeys over his front nine, but recorded only one birdie on the back for his 69.
Rashell had an even crazier front nine than Davis did. Rashell tallied six birdies, two bogeys and only one par. He added birdies at 12 and 14, but dropped a shot at the last for his 67.
Greg Owen carded a 3-under 69 on Saturday and is alone in fourth place at 13-under-par 275. Dan Olsen, who was alone in second following the third round, struggled to a 4-over 76 and is tied for fifth with Will MacKenzie, who shot a 68 in the fourth round. That duo is knotted at 10-under-par 278.
Phillip Price, who shocked Phil Mickelson in the singles at the 2002 Ryder Cup, shot an even-par 72 and is tied for seventh place with John Elliott (71), Carl Paulson (66), Matt Davidson (70) and Omar Uresti (75). The group is knotted at 9-under-par 279.