Lewis was bogey-free en route to his 65 at the Old Course at St. Andrews and is at 15-under 129 after 36 holes. Joost Luiten, with a 30 on the front nine at Kingsbarns, turned in a 9-under 63 Friday in moving to 14-under for the tournament.
Peter Uihlein came close to posting the first 59 in the European Tour event, roaring through Kingsbarns with an 11-under 60. Uihlein had two eagles and seven birdies. He shot 29 on the front side -- his second nine on the day -- ending with pars at Nos. 8 and 9.
A birdie at either would have given him 59, a mark not achieved on the European Tour but is the PGA Tour record held by six players, the most recent Jim Furyk at this year's BMW Championship. Uihlein recorded the 17th 60 on the European Tour.
Lewis was among five players tied for the lead after Thursday's tournament first round. The logjam loosed only slightly after Friday's play. While Lewis is alone in first, one stroke ahead of Luiten, six players -- including Uihlein -- are at 13-under and three more are three strokes off Lewis' pace.
The tournament is played on three courses, with each player scheduled for a round at either St. Andrews, Carnoustie and Kingsbarns the first three days. The tournament wraps up Sunday at the Old Course.
Carnoustie is considered the toughest of the three courses and Lewis is yet to have his round there. Luiten, who had his 63 at Kingsbarns, played Carnoustie in the first round, shooting 5-under 67.
The group at 13-under includes Hennie Otto, who matched Luiten's 63, only at St. Andrews. Also two behind Lewis are Tommy Fleetwood and Mark Foster, who each shot 66 Friday; and Richard McEvoy and Oliver Wilson, with second rounds of 67.
Lewis, starting on the back nine at St. Andrews, opened Friday with five pars but was able to make the turn at 3-under. He had five birdies over Nos. 3-8 in moving into the lead.