That might not be low enough.
Langer shot a 6-under 64 on Saturday to move to 10 under for the tournament, putting him ahead of a big-name field by four strokes.
''That's not a huge lead,'' he insisted. ''That can disappear in no time. I'm going to have to get out there and shoot under par. That's my goal.
''If I go 2 under or 3 under, it will be very difficult for anyone to catch me. And if they do, they deserve to win.''
The two-time Masters champion opened with three straight birdies and eight in 12 holes at Indianwood, a course with tight and unforgiving fairways and undulating greens.
''He didn't win two Masters by luck,'' said, who was in a five-way tie for second place. ''He's an exceptionally good player, very methodical.''
Langer didn't miss a green in regulation during the third round until the par-3 No. 13, where a double bogey cut his cushion to three shots. He bounced back with a birdie at 15 before giving that stroke back with a bogey at 18.
Couples surged up the leaderboard with a 65 after starting the day tied for 25th place. He was part of a pack - along with Fred Funk and Jay Haas - that was five shots back in a tie for seventh at the Champion Tour's fourth of five majors.
What did Couples think it would take to get into contention with Langer in the final round?
''Sixty,'' he said. ''How does that sound? Does that sound pretty good? Not really realistic.
''He's not going to come back. Corey and whoever is going to have to play a remarkable round to win. I'm at least inching closer.''
While Langer was in his sensational stretch Saturday, first-round leader Tom Kite and second-round leader Lance Ten Broeck were struggling in the final group.
Kite finished with a 74 to drop into a tie for 17th, nine shots back. Since opening with a U.S. Senior Open nine-hole record 28, Kite is 6 over.
Ten Broeck, a full-time caddie for Tim Herron and occasional player, shot a 72 with three birdies and five bogeys. He is alone in 11th place, six shots back, after starting the round with a one-shot lead over Kite and a two-stroke edge on a group that included Langer.
Pavin was tied with Langer coming in and finished the third round four shots back, insisting he only thought about a two-stroke penalty from Thursday when a reporter asked about it. After pulling into a first-round tie for the lead, Pavin was docked two shots for hitting a ball that moved a fraction of an inch when he grounded his club to prepare for a chip.
Couples, who said that his chronic back problems have kept him from ever practicing for a Champions Tour event, got into contention by driving the green at the 360-yard, par-4 No. 9 and posting an eagle from 105 yards on the next hole that created a buzz on the course.
''You know it's going to be close when they start to ooh and aah,'' he said. ''As it went closer, they threw their hands up. Yeah, it's a great feeling. You don't make many eagles, especially from the fairway.''
Langer scored with his flat stick, making a pair of 20-foot-plus putts for birdies on the first two holes while building confidence on a course set up to be a tough test for the best 50-and-older golfers in the world.
The 54-year-old German has nine top-10 finishes in his 11 previous Champion Tour events this season, including three runner-up showings, and is shooting for his first win since needing surgery to repair a torn ligament in his left thumb last year.
Langer sounds as if he's back to being the golfer that led the senior circuit money list from 2008-2010 - each of his first three seasons on the Champion Tour - before slipping to 25 last year because of a surgery-stunted season.
''Without being big headed, I think I'm one of the better players out here the last three or four years,'' he said. ''I've won the Schwab Cup. If you do that, you've got to play well. If you can win normal tournaments and be in the top five or top 10 on a regular basis, you ought to be doing fairly well in the majors too because the majors are even harder.
''The better players, I think, will separate themselves even more from the average player in the majors because conditions are usually tougher.