Lundberg stands at 12-under-par 204 for the tournament, one stroke clear of fellow Swede and overnight leader Fredrik Widmark and France's Sebastien Delagrange, who share second place.
'I'm looking forward to tomorrow,' said Lundberg. 'There is no better feeling in the world than when you are up there on the leaderboard. I have that great feeling of excitement.'
Lundberg is leading after three rounds for the first time since 2001, when he posted a final-round 80 at the European Open to fall into a tie for 34th place.
'I don't think that matters anymore,' said Lundberg, who qualified for the European Tour through the Challenge Tour in 2000. 'There were a lot of things that caused me to play badly that day -- it wasn't just down to me, so I don't really look back on it badly.
'That was the first time that I had been in that position and it was a bigger event than this. I learned a lot from it, and it gets better and better.'
Widmark struggled early but finished at 1-under 71 in his third round, while Delagrange fired one of two 6-under 66s -- the low score Saturday -- to climb up the leaderboard.
First round leader Peter Whiteford (67) is alone in fourth place at 10-under-par 206, one stroke ahead of three players tied for fifth at minus-9.
This tournament is the third dual-ranking event of the 2005 season for the European and Challenge Tours. And with the PGA Championship being played eight time zones away, no player ranked in the Order of Merit's top-100 is in the field.
'Everybody here wants to be in the position I am in now,' acknowledged Lundberg. 'It's the best, and that is why we all play the game.'
While Widmark stumbled to consecutive bogeys at the par-5 second and the par-4 third, Lundberg kept it steady and opened with five straight pars to take over the lead from his playing partner.
Delagrange, who collected four birdies on the front nine, and England's Shaun P. Webster, who shared third place with countryman Ben Mason overnight, were there too. They briefly shared the lead with Lundberg, who wasn't too happy with his start despite moving into the lead early on.
'My score was good today, but the game wasn't too good,' said Lundberg. 'I made a bit of a rocky start today...but it got better and better, and by the end of the round it felt all right.'
Both Lundberg and Widmark dropped in birdies at the par-4 sixth -- with Lundberg moving to 10 under for the outright lead -- but Widmark stumbled to another bogey at No. 9 to make the turn at minus-8.
Meanwhile, Lundberg continued to par his holes, making seven straight after his birdie at the sixth. Both players then birdied the 399-yard, par-4 14th for two of the combined five birdies they collected on their final five holes.
All in all, eight players are within four strokes of Lundberg heading into the final round.
England's Ben Mason (71) and Andrew Butterfield (69) and Jesus Maria Arruti (70) of Spain share fifth place at 9-under-par 207, while France's Bertrand Cornut (67) and Aussie Jarrod Moseley (68) are one stroke further back.
Webster (73) is among a group of five players tied for 10th place at 7-under-par 209. Jamie Spence of England shot the day's other round of 66 and is tied with six other golfers at minus-6.