Lundberg, who shared the overnight lead with fellow Swede Jarmo Sandelin, has a 17-under 199 total. Jamie Moul of England, who started the day tied for 11th place, was in second after a bogey-free 64, the days best round.
Englands Benn Barham (65) and Michiel Bothma of South Africa (66) were tied for third at 14-under 202.
Sandelins 72 left him tied for fifth with Darren Fichardt of South Africa and Englands Robert Rock, four strokes off the lead.
Lundberg, who won the 2005 Russian Open on the fourth extra hole of a playoff for his first European Tour title, recovered from a bogey on the opening hole to birdie the next two and the par-5 fifth. After bogeying the seventh, when he chipped from one bunker to another, he birdied the 11th and made an eagle on the par-5 15th.
Still, he was not satisfied with the round.
I have gotten worse throughout the week, Lundberg said. Today I played not good at all but with a few good shots, and I managed to get it to four under ' I dont know how.
Lundberg also finished third here in 2006.
I won with 15 under and then finished third with 17 under so the standard is going up all the time. Im still leading, but 18 holes is still a long way to go.
The 23-year-old Moul made five birdies on the front nine and birdied his three last holes on the back, including a two-yard putt on No. 18.
Lundberg missed a nearly identical birdie putt on the same hole for a chance to take a two-stroke lead.