"It's not science here," Watson said. "It's try to hit the greens. And if you're hitting the greens, that means you're obviously hitting your tee shots well. So that's all I'm trying to do is just hit the greens … maybe throw in a birdie here or there. That's what I've done the last two days and it's worked out so far."
Watson made bogey on the 18th hole with a shot that bounced left of the green and into the gallery. He finished at 7-under 137, giving him the largest 36-hole lead at the Masters since Chad Campbell in 2006.
Senden qualified for the Masters a month ago with his win at Innisbrook. After a rugged start, he played the final 14 holes with six birdies and no bogeys for a 68 that puts him in the last group at a major on the weekend.
Adam Scott also made a late recovery with three birdies on the back nine to salvage a 72, along with his hopes to join Tiger Woods, Nick Faldo and Jack Nicklaus as the only players to win back-to-back at Augusta. Scott was four shots back at 141, along with Thomas Bjorn (68), Jonas Blixt (71) and Jordan Spieth, the 20-year-old from Texas who looked solid on the mystifying greens and shot a 70.
"Bubba is tearing it up," Spieth said. "So we've got to go get him."
The chase includes the ageless Fred Couples, who won the Masters a year before Spieth was born. Couples, cool as ever at 54, had another 71 and was five back.
Woods, who missed the Masters for the first time in 20 years because of back surgery, won't be the only guy watching on television. Phil Mickelson made another triple bogey three shots from the bunkers on the par-3 12th hole for a 73 and missed the cut for the first time since 1997. So did Sergio Garcia, Ernie Els, Luke Donald, Webb Simpson, Dustin Johnson and Jason Dufner.
Rory McIlroy nearly joined them. He hit one tee shot over the fourth green, past the head of Adam Scott on the fifth tee and into the bushes for a double bogey. Another shot hit a sprinkler head and landed in the azaleas behind the 13th green. He had to make a 6-foot par putt to make the cut at 4-over 148. Watson seems further away from the field than just three shots.
U.S. Open champion Justin Rose was nine shots behind, but not ready to give up because the leader often comes back to the field although he admitted that former champs are less likely to collapse.
"But there's no give on this golf course," Rose said. •
Saturday's tee times
8:15 a.m. • Rory McIlroy
8:25 a.m. • Jason Day, Joost Luiten
8:35 a.m. • J.M. Olazabal, Darren Clarke
8:45 a.m. • M. Angel Jimenez, Sandy Lyle
8:55 a.m. • Billy Horschel, Gary Woodland
9:05 a.m. • Chris Kirk, Martin Kaymer
9:15 a.m. • a-Oliver Goss, F. Molinari
9:25 a.m. • Nick Watney, Thongchai Jaidee
9:35 a.m. • Bill Haas, Thorbjorn Olesen
9:55 a.m. • Ian Poulter, Rickie Fowler
10:05 a.m. • S. Bowditch, Brendon de Jonge
10:15 a.m. • Hunter Mahan, Justin Rose
10:25 a.m. • Vijay Singh, Bernhard Langer
10:35 a.m. • Steve Stricker, Larry Mize
10:45 a.m. • Mike Weir, K.J. Choi
10:55 a.m. • Henrik Stenson, Stewart Cink
11:05 a.m. • Lee Westwood, Brandt Snedeker
11:15 a.m. • Louis Oosthuizen, Gonzalo Fernandez-Castano
11:35 a.m. • Lucas Glover, Matt Kuchar
11:45 a.m. • Kevin Stadler, Jamie Donaldson
11:55 a.m. • Stephen Gallacher, Russell Henley
12:05 p.m. • Jim Furyk, Kevin Streelman
12:15 p.m. • Fred Couples, Jimmy Walker
12:25 p.m. • Adam Scott, Jordan Spieth
12:35 p.m. • Thomas Bjorn, Jonas Blixt
12:45 p.m. • Bubba Watson, John Senden