Back-to-back eagles at her final two holes enabled England's Melissa Reid to move six shots clear of the field at the Nykredit Masters in Denmark.
Reid added a seven-under-par 66 to her opening 67 to finish 13 under at Simon's Golf Club near Helsingor.
Former world number one Annika Sorenstam, making her last appearance in Europe as a professional golfer, shot 68 to share second with Germany's overnight leader Martina Eberl (73) on seven under.
Derbyshire 20-year-old Reid carded three straight birdies from the sixth then bogeyed the 14th before picking up five strokes over her closing three holes.
After hitting a brilliant shot to eight feet at the par-four 16th, Reid rolled in a 35-footer for eagle at the 513-yard 17th hole before chipping in from the front of the green at the par-five last.
"Today I struck it a lot better," said Reid, who has two second-place finishes this year.
"I've had a couple of good weeks practice and I was just trying to keep it simple. I missed a couple of short five-footers but overall I was pretty happy.
"You can't complain about the finish: birdie-eagle-eagle."
Reid will play with long-term heroine Sorenstam in the final round and she added: "It's so weird. I have pictures of her and stuff in my room still and I have her book right next to me on the bed.
"It would be pretty cool if I won the tournament and I played with her in the final round. That would really be a win in style."