Wales' Lydia Hall slipped to second in the Lalla Meryem Cup at Royal Golf Dar Es Salam in Rabat, Morocco.
Hall, 29, hit a two-over-par 74 to finish her third round on five under par, one stroke behind Norwegian Suzann Pettersen.
England's Annabel Dimmock is a further stroke back and one ahead of compatriot Felicity Johnson.
Wales' Hall and Pettersen will play in the final pair tomorrow, teeing off at 9.40 BST.
Hall is still hopeful of victory despite a disappointing day.
"I got to two-under for the day after six holes but one poor decision and I didn't execute the shot on the par-five, sixth," she said.
"That cost me a shot and then a poor swing on seven cost me another shot. I managed to get up and down to save my bogey but it was one poor decision and then one bad swing. It was tricky in the middle part of the round.
"I stood on the 10th tee thinking of getting back to level par and pulled a tee shot on the left, but I settled the ship through 13, 14 and gave myself an opportunity on 17 to pull one back, so I'm in a good position for tomorrow.
"Yesterday I had no bogeys on the card, so that was really pleasing. It is going to bite you at some point, you've only got to miss five yards off the fairway and your underneath trees or in thick rough. The keys for me are to hit fairways and see how many greens in regulation I can get and then see what I can do with the putter."