Zach Johnson's last three opening rounds: a 65 at the Travelers Championship, 64 at the John Deere Classic, and on Thursday a 66 at The Open Championship.
The latter is just a stroke off his opening round in the Open a year ago. He went on to tie for ninth.
Johnson owns just five rounds in the 60s in 31 overall at the Open (66/R1/2013, 66/R3/2012, 65/R1/2012, 68/R2/2011, 68/R3/2007).
First-Round Leader Stats
Since 1975, just five first-round leaders of The Open Championship have gone on to win: Tiger Woods (2005), John Daly (1995), Greg Norman (1993), Seve Ballesteros (1988) and Tom Watson (1980).
The lowest opening-round score at the Open Championship is 63, set by Rory McIlroy at St. Andrews in 2010.
The best opening-round score at Muirfield is 64, set by Rodger Davis (1987), Raymond Floyd (1992) and Steve Pate (1992).
In the 15 previous Open Championships hosted by Muirfield, the first-round leader has gone on to win three times (Ted Ray/1912, Jack Nicklaus/1966, Tom Watson/1980).
The first-round leader/co-leader has gone on to win just six of 28 stroke-play events on the PGA TOUR in 2013, most recently Harris English at the FedEx St. Jude Classic.
Defending champion Ernie Els carded a 3-over 74 Last year, he posted an opening-round 67 en route to his second Claret Jug.
Els is seeking to become the seventh player with consecutive Open Championship victories since 1951: Padraig Harrington (2007-08), Woods (2005-06), Watson (1982-83), Lee Trevino (1971-72), Arnold Palmer (1961-62) and Peter Thomson (1954-56). Sixteen players have performed the feat throughout Open history.
Els is making his third Open start at Muirfield (T5-1992, 1-2002).
Most rounds in the 60s in Open Championship history (39-Els, 37-Nick Faldo, 33-Jack Nicklaus).
Most under-par rounds since 1963: 59 (Nicklaus), 53 (Faldo), 48 (Els), 45 (Watson).
Miguel Angel Jimenez’s 3-under 68 marks the sixth time in his last nine Open Championship starts that he has opened with a round in the 60s.
Phil Mickelson’s 2-under 69 is just his third opening round in the 60s in 20 starts at the Open Championship, with two of the three coming at Muirfield (2002/68, 2006/69, 2013/69).
2004 Open champion Todd Hamilton opened with a 2-under 69. In 33 rounds at the Open Championship, his only other rounds in the 60s came en route to his victory in 2004 (71-67-67-69).
Jason Day recorded a 2-over 73 Thursday in his third Open Championship start (T60-2010, T30-2011). He is the only player with top-10 finishes in the first two major championships this year (3rd-Masters, T2-U.S. Open).
Reigning U.S. Open champion Justin Rose posted an opening-round 4-over 75 in his 12th Open Championship start. His lone top-10 finish at the event remains a T4 in his inaugural start in 1998. Rose is seeking to become the seventh player to win the U.S. Open and Open Championship in the same season: Bobby Jones, Gene Sarazen, Ben Hogan, Lee Trevino, Tom Watson and Tiger Woods.
Rory McIlroy’s 8-over 79 fell one shy of his worst round at the Open Championship (R2, 2010 at St. Andrews).