Tom Watson negotiated the front nine at a tricky Turnberry in one over par to sit alone at the top of the Open Championship leaderboard at -4.
The 59-year-old recorded six pars, bogeys at the 6th and 9th and birdie at the 7th as his challengers struggled to make par.
Joint overnight leader Steve Marino started badly with five dropped shots in his first five holes but bounced back well with an eagle at the par 5 7th for a -2 total through nine holes.
Watson's nearest challenger is England's Ross Fisher, whose wife is expecting their first child any day, is a shot back on -3. He's looked in control with a birdie and a bogey in a lefvel par 35 for the front nine.
A large group are circling on -2, including Lee Westwood, Retief Goosen and Matthew Goggin. Only nine players remain under par.
A 67 from Bryce Molder and a 69 from Thongchai Jaidee for even par totals of 210 have seen the pair surge up the leaderboard into a tie for 11th, and they may well find themselves in the top 10 by the time the last putt has been holed today.