Oliver Wilson missed a chance for a share of the lead at Doral with a disappointing final hole as Padraig Harrington made a welcome return to form at the WGC-CA Championship.
England's Wilson held a share of the opening-round lead at seven under par as he played the par-four, 443-yard 18th hole but landed his second shot in water short of the green on the way to a double-bogey six.
That left the 2008 Ryder Cup player with a first-round 67 on day one of this 80-player, no-cut event, two shots back of clubhouse leaders Jeev Milka Singh of India, Thailand's Prayad Marksaeng, South African Retief Goosen and American Phil Mickelson, who each carded 65s on the par-72, 7,266-yard Blue Monster course.
"Yes, very frustrating," Wilson said of his final hole blunder.
"It is a tough hole, though, you know. I hit a great drive but I think that is the toughest pin on that green to be honest.
"I was more concerned missing the green right rather than left and I was just a bit in between clubs and didn't really concentrate properly and hit a bad shot.
"It was a shame not to hole the putt for five, that would have been all right but I played all right, it was a good round apart from that so I'll try and take that forward into tomorrow and the rest of the week."
Ireland's Harrington, the Open and US PGA champion, bounced back from a first-round WGC-Accenture Match Play Championship exit to Pat Perez two weeks ago and two missed cuts in his first four starts of the year prior to that.
The Irishman birdied three holes on his front nine and three more at the start of his inward nine on the way to six-under-par 66, one shot off the lead alongside American Nick Watney, Australia's Rod Pampling and James Kingston of South Africa.
"I'm very happy," Harrington said. "Obviously I have not had a great run of form so far this year so it's nice to shoot a good score.
"I was probably a little more focused on my scoring this week than necessarily anything else so it's nice to get out and shoot a decent number.
"I certainly didn't hit the driver very well today but, again, my head seemed to be in the right place and I hit my irons well, short game was good.
"So all of those things added up to a 66."
Joining Wilson in the clubhouse on five under were Louis Oosthuizen of South Africa, American Sean O'Hair, Argentina's Andres Romero and Colombia's Camilo Villegas, who had begun his day in the worst possible way.
Villegas, a big crowd favourite in Miami, gave his Latin American fans palpitations with an awful start to his round at the par-five 10th, four-putting from the fringe of the green for a bogey six before making amends over the next 17 holes.
Rory McIlroy got off to a great start and saw his round unravel slightly on the back nine.
The Northern Ireland 19-year-old, a quarter-finalist at the WGC-Accenture in his first Stateside tournament as a professional and tied for 13th place in last week's Honda Classic, eagled the first hole and was five under after 12 holes before bogeying the 13th and 14th.
McIlroy hit back with a birdie two at the 16th and finished four under with Americans Jim Furyk and Charley Hoffman.
World number one Tiger Woods continued his comeback from knee surgery but was not firing on all cylinders in a solid if unspectacular opening round.
Woods, playing in his first stroke-play event in nine months, carded a two-bogey, three-birdie round of 71 but was happy with his play if not a little perplexed.
"It was a little bit frustrating on those greens today," Woods said. "I hit so many putts that looked good.
"I thought I hit my lines and thought I had the right speed but they just didn't go in.
"I have to be a little bit sharper tomorrow, hopefully those putts go in and the score will be a little different."
Luke Donald carded a three-under 69 to make light of his wrist injury scare at the WGC-Accenture Match Play two weeks ago, while Ian Poulter, another of the eight Englishmen in the field this week, finished at two under.
Of their compatriots, Paul Casey recovered from three over par after six holes to finish with a one-under round of 71, the same score as Lee Westwood while Richard Finch and Ross Fisher were in the clubhouse on level par and Justin Rose posted a 73.
Northern Ireland's Graeme McDowell was another on one over par while compatriot Darren Clarke carded a round of 74, two over.
Collated first-round scores (USA unless stated, par 72):
65 Jeev Milkha Singh (Ind), Phil Mickelson, Retief Goosen (Rsa), Prayad Marksaeng (Tha)
66 Nick Watney, Rodney Pampling (Aus), James Kingston (Rsa), Padraig Harrington (Irl)
67 Sean O'Hair, Andres Romero (Arg), Oliver Wilson (Eng), Camilo Villegas (Col), Louis Oosthuizen (Rsa)
68 Rory McIlroy (NIrl), Charley Hoffman, Jim Furyk
69 Steve Stricker, Rory Sabbatini (Rsa), Vijay Singh (Fij), Justin Leonard, Robert Allenby (Aus), Miguel Angel Jimenez (Spa), Boo Weekley, Ian Poulter (Eng), Luke Donald (Eng), Henrik Stenson (Swe)
70 Pat Perez, Garth Mulroy (Rsa), Zach Johnson, Davis Love III, Soren Kjeldsen (Swe), Peter Hanson (Swe), Kenny Perry, Dustin Johnson, Ernie Els (Rsa), Ryuji Imada (Jpn), Briny Baird, Shingo Katayama (Jpn), Richard Sterne (Rsa)
71 Dudley Hart, Tiger Woods, Ross Fisher (Eng), Adam Scott (Aus), Ben Curtis, Hunter Mahan, Paul Casey (Eng), Robert Karlsson (Swe), Anthony Kim, Mike Weir (Can), Ken Duke, Tim Clark (Rsa), Lee Westwood (Eng), Stuart Appleby (Aus)
72 Chad Campbell, Sergio Garcia (Spa), Richard Finch (Eng), Bubba Watson, Stephen Ames (Can), Alvaro Quiros (Spa)
73 Y. E Yang (Kor), Justin Rose (Eng), Graeme McDowell (NIrl), K J Choi (Kor), Geoff Ogilvy (Aus), Martin Kaymer (Ger), Stewart Cink, Mark Brown
74 Thomas Aiken (Rsa), Trevor Immelman (Rsa), Soren Hansen (Den), Kevin Sutherland, Darren Clarke (NIrl), Carl Pettersson (Swe)
75 Aaron Baddeley (Aus), Billy Mayfair, Wen-Tang Lin (Tai)
76 John Rollins, Pablo Larrazabal (Spa)
77 Azuma Yano (Jpn), D.J. Trahan
Defensive end Antonio Smith, Houston Texans agree to 5-year, $35 million deal
Kurt Warner makes counterproposal to Arizona Cardinals
HULL LEADS THE WAY
