For the third consecutive day, Andrade will sleep on the lead at the SEI Pennsylvania Classic in Paoli, Penn.
Andrade shot 3-under 68 to finish 54 holes at 11-under-par 202. Hes one shot clear of Jeff Brehaut (66).
Ian Leggatt (69) is alone in third place at 9-under.
Dan Forsman (64), Steve Flesch (65), John Huston (65), John Senden (65) and Jeff Sluman (65) are all tied at minus 7.
Andrade started the day with a one-shot lead, but the scoreboard became crowded quickly Saturday as several in the morning groups posted low numbers.
Seven players shot 65 or lower, with Forsman tying the Waynesborough Country Club course record.
As many as eight players were tied for the top spot, at 8-under, before Andrade broke the deadlock with a birdie on par-4 13th. He promptly bogeyed 14, but again moved to minus 9 with a birdie at 15.
Brehaut tied Andrade for the lead by hitting his tee shot on the par-3 17th to a foot; it was his third consecutive birdie. He added a fourth in a row at the par-5 18th.
'I wasn't very sharp on the front, but something started clicking on 11, started hitting it close and made most of them - had a great finish with four birdies in a row,' Brehaut said.
The 11th was a pivotal hole for Andrade.
'The turning point of my round was bogeying 11. It put me at 7-under and I said, 'okay, all the guys that have played before me have played well and I need to get off the pot - get going,'' Andrade said.
After the birdie-bogey-birdie run on holes 13-15, Andrade made another birdie on 16 to get to double digits under par, and then splashed his bunker shot to two feet on 18 for his fifth birdie over his final seven holes.
While Andrade is in his 15th season on the PGA Tour, Brehaut is a career Buy.Commer. He spent nearly the entire decade of the 90s on the developmental tour, winning in 1995 and 97.
This is his third season on the big tour. He underwent shoulder surgery at the start of 2000 and competed in only one event. Thanks to a Major Medical Extension he played in 26 events last year, but finished 181st on the money list.
After a return trip to Q-School, he made his way back to the primary circuit in 2002, where he had missed 12 cuts in 21 starts prior to this week. Hes currently 188th on the money list.
Defending champion Robert Allenby heads a group of players at 7-under-par. The Aussie used a 5-iron to ace the 210-yard, par-3 17th en route to a 4-under 67.
Sunday's final round has been pushed up due to the threat of inclement weather. Players will go out at 7:00 AM ET in threesomes on split tees.
Full-field scores from the SEI Pennsylvania Classic