Updated

Losing in a playoff last week did not deter Zach Johnson. The former major champion opened the British Open with a 5-under 66 on Thursday to take a 1-stroke lead after the opening round.

The 2007 Masters champion has never led after any round at the British Open, and his 66 matched his second-best score at the year's third major.

Former Open champion Mark O'Meara carded a 4-under 67 and was joined in second place by Rafael Cabrera-Bello. O'Meara, the 1998 winner, posted his best score at the British Open since the first round in 2009.

A trio of Americans - Brandt Snedeker, Dustin Johnson and 1996 British Open champ Tom Lehman - started with 3-udner 68s. They were joined in fourth place by Miguel Angel Jimenez and Shiv Kapur, who started with six birdies in the first seven holes at Muirfield Golf Club. Kapur dropped three strokes on the back nine to fall down the leaderboard.

Three-time champion Tiger Woods and Scottish Open winner Phil Mickelson are tied for ninth at minus-2. Jordan Spieth, who won last week's John Deere Classic to get the last spot in the field this week, stands alongside Woods and Mickelson, as do Francesco Molinari, Angel Cabrera and 2004 Open champion Todd Hamilton.

Bubba Watson and Henrik Stenson are among six players tied for 15th at minus-1 as 20 players scored in red figures in the opening round.

Jason Day and major champions Padraig Harrington and Webb Simpson struggled to 2-over 73s on Thursday, while defending champion Ernie Els and Matt Kuchar stand at plus-3.

A large group of players faltered to 4-over 75s and share 77th place. Among that group were Fred Couples, Sergio Garcia, Geoff Ogilvy, Tom Watson, U.S. Open champion Justin Rose, Graeme McDowell, Nick Watney and Keegan Bradley.

Zach Johnson, who lost to Spieth in a playoff last week, did most of his scoring in a five-hole burst on the front nine.

The 37-year-old birdied the third to get into red numbers. He poured in an eagle effort at the par-5 fifth to jump to 3-under.

Johnson followed with back-to-back birdies at six and seven to gain a share of the lead at minus-5. He ran off four pars in a row from the eighth before being the first to 6-under with a birdie on the 12th.

At the 14th, Johnson stumbled to a bogey to cut his lead to one. He wrapped up his round with four consecutive pars to hold the lead.

"Very pleased. It was a very solid day. I felt great," Johnson stated. "I had some good numbers to hit some shots close, because that is part of it here, as firm as it is. Anytime you shoot under par in an Open or a major, for that matter, you have to be putting at least somewhat decent, and I putted great.

"I made some nice birdie putts and obviously that one for eagle. But I struck some really nice solid par putts. That's what you've got to do to stay in it. All in at all, very solid, just it's just one round."

Jimenez was in control early as he started with birdies on each of the first three holes, with another birdie at the fifth. After a trio of pars, he birdied the ninth to make the turn with the lead at minus-5.

However, Jimenez dropped shots at 12 and 16 to fall two shots off the pace.

O'Meara collected back-to-back birdies from the first and again from the fifth. He grabbed a share of the lead with a birdie on the ninth.

Around the turn, O'Meara tripped to a bogey at the 10th. He later dropped shots at 14 and 15 to dip to minus-2. O'Meara bounced back with an eagle at 17 to grab a share of second.

Cabrera-Bello birdied three of four holes from the second. He dropped a shot at nine, but erased that error with birdies at 11 and 13. The Spaniard dropped another stroke at 15, but birdied the 17th for a 67.

Woods pulled his first tee shot into the thick grass. After taking an unplayable lie penalty, he scrambled to a bogey. He went on to birdie four and bogey No. 6.

On the back nine, he birdied three of the first four holes from the 10th. Woods bogeyed 14 and 2-putted for birdie at 17 for his 69.

"I mean, it was amazing, when I got over that tee shot, I thought, if I hammer it, this 3-wood is in that bunker. So maybe I should take something off it. Maybe I should hit 5-wood. Hence I hit a flip hook left and there she goes," Woods said of his opening tee shot. "I took an unplayable, hit the shot where I wanted to, hit it right of the hole and I got up and down."

Mickelson had two birdies and a bogey on both nines.

"I played well. I had a spurt there in the middle of the round where I had some technical difficulties and hit some poor shots, but was able to make pars and then turned it around," Mickelson admitted. "I kind of keyed in on it after the par on 13, and from there on in I hit a couple of good shots and made a couple of birdies coming in."

Among the players that really struggled were Matteo Manassero (76), Bill Haas (77), Rickie Fowler (78), Rory McIlroy (79) and Luke Donald (80).

NOTES: Zach Johnson leads for the first time after any round of the British Open in his career ... Cabrera-Bello's best finish in a major is a share of 47th at the 2010 U.S. Open ... The Spaniard shared 81st last year and he posted a round in the 60s for the first time in his career at the Open Championship.