The two Scandinavians were paired together after 36 holes but the positions were reversed as the third round unfolded with Lundberg shooting 69 to his compatriot's 71.
Lundberg, who had birdies at the sixth, 14th and 16th, finished on 204, 12 under par, and leads by one going into today's final round from Widmark, who recovered from an outward half of 38 to come home in 33, and France's Sébastien Delagrange.
"The score was good but the game wasn't too good. I made a rocky start but it got better and better, and by the end of the round it felt all right," said Lundberg, who is looking to regain the European Tour card he lost last year. "There's no better feeling than when you're up there on the leaderboard. Everyone here wants the position I'm in now."
Delagrange carded a bogey-free, six-under-par 66 with four birdies on the front nine and two coming home.
The leading British player is 25-year-old Scot Peter Whiteford, who briefly led on 11 under with Delagrange before bogeying the last for a 67 and a 10-under-par total.
Whiteford, who started the day on five under, went to the turn in 35 before igniting with birdies at the 11th, 16th and 17th and an eagle on the 561-yard 15th when he chipped in from 40 yards. "The eagle definitely kick-started it for me as I then hit it close on the next hole, a par-three. I'm delighted," said Whiteford, who lost a play-off to fellow Scot Marc Warren at last week's Ireland Ryder Cup Challenge.
Another Englishman, European Tour veteran Roger Chapman, holed in one on the par-three fourth, but missed out on a new Cadillac because a car is only on offer at the short 16th.Reuse content