Henrik Stenson fired a 6-under 66 on Saturday to grab a 2-stroke lead after three rounds of the Scottish Open.
Stenson finished 54 holes at 16-under-par 200. He will go for his eighth European Tour title on Sunday.
Phil Mickelson, who has never won an official European Tour event, also posted a 66 to move into a share of second place at minus-14 at Castle Stuart Golf Links.
Branden Grace and John Parry also carded 66s to grab a share of second, while JB Hansen managed a 3-under 69 to finish three rounds at minus-14.
Gareth Maybin and Raphael Jacquelin had the two lowest rounds of the day as they shot 64 and 65, respectively, to move into a tie for sixth at 13-under- par 203. The stand alongside American Peter Uihlein, who bogeyed the par-5 finishing hole for a 2-under 70.
Chris Doak, the second-round leader, struggled to a 1-over over 73 and tumbled into a share of 12th at minus-11. He leads the Scottish contingent that hasn't had a winner since 1999, when Colin Montgomerie won the crown.
Stenson trailed by two at the start of the round, but got off to a quick start with birdies at one and three. He moved to 13-under with a birdie at the sixth, but he gave that shot back when he bogeyed the par-4 ninth.
The 37-year-old Swede bounced back with a birdie on the 11th. The two-time European Ryder Cup performer birdied the 12th for the third round in a row to move into a share of the lead at minus-14 with Grace and Mickelson.
Stenson moved in front with a birdie at the 14th. After three pars in a row, he got up and down for birdie at the last to push his lead to two after three rounds.
"I was just very happy with my round. Yesterday, I went up to the range and had a session and really felt like I was hitting the ball nicely, and I carried that onto the course today," Stenson said. "It was as good as I felt all year, tee-to-green. It was tricky at times, though."
Mickelson ran off seven consecutive pars to start his third round. After converting a birdie chance at the par-3 eighth, he birdied the ninth and 10th, both from inside seven feet, to move to 11-under.
At the 12th, Mickelson rolled in a 12-footer for birdie. He wrapped up a bogey-free round with birdies at 16 and 18 to end at 14-under.
"It felt good to get the round going after a slow start the first seven holes with no birdies, to turn it around and make six in the last 11 holes felt great," Mickelson stated. "To put myself in position to have a chance tomorrow, it's a lot of fun. It's why we play. I'll be looking forward to it."
Parry also had a bogey-free round with two birdies on the front nine and four more around the turn.
Grace flew out of the gate with four birdies in the first five holes to soar to 12-under par. He parred nine of 10 holes from the sixth. In between those pars, he birdied the 11th.
The South African, who won four times on the European Tour last year, wrapped birdies at the 16th and 18th around a bogey at the 17th.
Hansen was the last one to post 14-under. He had two birdies and two bogeys on the front nine. Around the turn, he mixed four birdies and with a lone bogey at the 15th to gain a share of second place.
NOTES: Stenson owns the 54-hole lead for the eighth time on the European Tour ... He has won just three of the previous seven times he was in this position ... Matteo Manassero had a hole-in-one on the par-3 eighth.