Davies, who had shared the lead after 18 holes, sank a nice 10-foot birdie putt at the 16th hole to get within a shot of Donald and then collected another 10-foot birdie on the 17th to grab a share of the top spot, firing a five-under 67 for the day.
The performance tied with Donald (68) atop the leaderboard at 16-under 200. Donald, who was paired with Davies, didn't make a birdie after the 10th, surrendering sole possession of the lead after holding at least a share throughout the first two rounds.
Two strokes back was Francesco Molinari (65), who collected an eagle on the 16th hole. Standing at 13-under 203 was Spaniard Alvaro Quiros (64), while Graeme Storm (67) was at 12-under 204.
Robert Rock (67) and Jamie Donaldson (70) were tied at 205.