RIDGEDALE, Mo. – Shane Bertsch shot his second straight 7-under 64 on Thursday to take a four-stroke lead into the final round of the Charles Schwab Series at Bass Pro Shops Big Cedar Lodge, his second event on the PGA Tour Champions.

"I don't think I've ever had a four-stroke lead going into the final day, but I feel like if I keep doing what I'm doing, I should have plenty of looks," Bertsch said. "And I'm making some putts, so, I'd rather it's four than three. I kind of struggled up the last hole, but I was glad to get a par in there."

Tied for the first-round lead with Tom Lehman, Bertsch had nine birdies and two bogeys at Buffalo Ridge in the first of two 54-hole events at Big Cedar Lodge.

"It's fun when you get rolling like that," Bertsch said. "I had a couple streaks where I think I made three in a row twice."

The 50-year-old Bertsch, a three-time winner on the Korn Ferry Tour, made his delayed senior debut three weeks ago with a tie for 45th in The Ally Challenge in Michigan.

"I knew that I could be there just from my first tournament, how I played and how my body was feeling and know how close I was at the The Ally," Bertsch said. "I really wasn't close in the end, but I felt like my game was, you know, adequate to play out here and I just need to get a little consistency going."

Bernhard Langer had a 64 to move into a tie for second at 10 under with Kenny Perry (65) and Wes Short Jr. (66).

"I kept the ball in play, hit a lot of fairways, lot of greens, gave myself a lot of opportunities and putted decent," Langer said. "You know, 7 under is very nice any time, but the conditions were gorgeous."

The 62-year-old German star won in Tucson, Arizona, in March for his tour-record 41st victory.

Perry eagled the par-5 18th.

"I hit the prettiest 5-wood I've hit in a long time into that green and made about a 20-footer," Perry said. "At least it kind of gets me in the ballpark."

Vijay Singh (66) and Darren Clarke (67) were 9 under.

Lehman had a 71 to drop into a tie for 11th at 7 under.