At 10-under 200, the Tennessee standout is three stroke clear of Jiri Zuska, who carded his third sub par round on Friday to stand at 7-under 203.
Lewis, who has held or had a share of the lead after each of the first three days in Johnstown, had eight birdies on his Friday card, including three in a row on holes 11-13, en route to a third round 66, which was the lowest score of the day at Sunnehanna Country Club.
It looked like Lewis was going to have some company atop the leaderboard for third straight days, as Zuska was enjoying a bogey-free round with five birdies through 15 holes. However, the Louisville senior gave three shots back with a double on the par-3 16th and a bogey on the 17th to finish with a 68.
Herman Sekne, who began the day tied with Lewis at 7-under, slipped down to into a tie for 13th following his third round 75.
