Germany's Sophia Popov grabbed a three-shot lead heading into the final round of the women's British Open at Royal Troon as she carded a bogey-free four-under-par 67 in the third round on Saturday.
The 27-year-old world number 304 equalled the lowest round of the week to put herself in contention for a maiden major title, posting an eagle and two birdies on another difficult scoring day.
Popov, who qualified for the Open with a top-10 finish at the Marathon Classic this month, showed great composure to sink a 30-foot birdie putt on the 17th hole as she cemented her position atop the leaderboard.
"I'm extremely happy. Four under and bogey-free is more than I could have hoped for," Popov said.
"I managed to not put myself in positions where I was freaking out. I was playing solid and that's because I was very patient.
"I'd be lying if I said I'm not going to be super nervous tomorrow morning - the nerves are going to be there so I need to realise that and play with them."
Australian Minjee Lee and Thailand's Jasmine Suwannapura are the only other two players under-par for the tournament, with both one-under overall after posting third-round scores of 69.
Two-times major champion Lydia Ko of New Zealand posted a hard-fought 72 to sit six strokes behind Popov and retain an outside chance of victory.
Overnight leader Dani Holmqvist, who was the only player to finish under-par on Friday, fell out of contention after a dismal round of 77.