Manley, looking for his first European Tour title, ended up with a 4-under-par 66 in the third round, which left him at 10-under 200 for the tournament. Shiva Kapur and Wade Ormsby, who both also shot 66 Saturday, are tied for second at 9-under.
Second-round leader Jbe Kruger suffered through a 3-over 73 and fell into a tie for 21st at 4-under.
Manley had three birdies and a bogey on each side Saturday. He tied for the lead with a long birdie putt at the seventh hole and had his tee shot at the 188-yard, par-3 eighth stop inches from the cup. A tap-in there put him in the lead alone.
He added birdies at Nos. 10 and 13 but slipped to bogey at 16. A 10-footer for birdie at 17 gave him the outright lead with one round to play.