Zach Johnson claims first round lead at The Open 2013
The Open: Zach Johnson is the first round leader after carding a five-under-par 66 at Muirfield
The 142nd Open Championship began in exactly the same way as the 141st, with American golfer Zach Johnson in imperious form, after carding an impressive five-under-par 66 to claim an overnight lead on the opening day at Muirfield.
The 37-year-old - who opened with a 65 at Lytham 12 months ago to sit in second-place - put the disappointment of last week's play-off defeat at the John Deere Classic title behind him, to storm to the turn in 31 thanks to an eagle and three birdies.
Johnson reached six-under on the 12th, before recording his only bogey two holes later, to finish the day with a one-shot lead over Spaniard Rafael Cabrera-Bello and 1998 Open champion Mark O'Meara on four-under-par.
Another shot back sits another Spaniard Miguel Angel Jiminez, and a trio of American's - Dustin Johnson, Tom Lehman, and Brandt Snedeker - as well as India's Shiv Kapur, who chipped in twice to card six birdies in his first seven holes before dropping back.
Last week's Scottish Open winner Phil Mickelson finished alongside world number one Tiger Woods, who recovered from a penalty drop after a poor drive at the first, to shoot a two-under-par 69.
They were joined by leader Johnson's John Deere Classic nemesis Jordan Spieth, as well as Italy's Francesco Molinari, two-time major champion Angel Cabrera and 2004 Open champion Todd Hamilton.
The British charge was led by England's Oliver Fisher and Scotland's Martin Laird, who both finished on one-under-par, one shot ahead of Australian, and reigning Masters champion Adam Scott.
Of the 156-strong field, only 26 players ended the first day at Muirfield on level par or better. The best of the rest saw 2011 Open champion Darren Clarke card a one-over-par 72, alongside Lee Westwood, who continues to chase his first ever major title in 62 attempts, and America's Jason Dufner, who will want to maintain his consistency from tee to green on the links course.
Defending champion Ernie Els - who was also the winner the last time The Open was staged at Muirfield in 2002 - carded a 74, while US Open winner Justin Rose finished day one on four-over-par 75, alongside Sergio Garcia of Spain, and Northern Ireland's Graeme McDowell.
Rory McIlroy also had a day to forget, scoring eight-over 79, which was one shot better than England's Luke Donald on a disappointing 80.
THE OPEN: FIRST-ROUND LEADERBOARD
-5: Z.Johnson (US) -4: Cabrera-Bello (Spa), O'Meara (US) -3: Jimenez (Spa), D Johnson (US), Snedeker (US), Lehman (US), Kapur (Ind) -2: Hamilton (US), Mickelson (US), Cabrera (Arg), Speith (US), Woods (US), F Molinari (Ita)
Notable others: Scott (Aus) +1: Clarke (NI), Westwood (Eng), Poulter (Eng) +3: Els (SA) +8: McIlroy (NI)