American Matt Kuchar sank a 30 yard bunker shot for an eagle three on his opening hole of the World Golf Championships-CA Championship but it was Robert Allenby who blazed into an early lead in windy Miami.
But it was good enough only for a share of the early lead as England's Simon Dyson, Dane Anders Hansen and Australian John Senden quickly reached two under par as well.
Dyson, on his first trip to the TPC Blue Monster course at Doral, went over the green in two at the long downwind first, but splashed out to two feet and then holed from 23 feet at the 236 yard fourth.
Both Rory McIlroy and playing partner Phil Mickelson, the defending champion, had to be content with fives on the 551 yard tenth - the hole where Kuchar began in style.
A hot pace was being set and Australian Allenby was the one leading the way at five under after he birdied the first and third, holed a 114 yard pitch for an eagle two on the fifth and collected another birdie on the next.
Two behind in joint second place were his compatriot Senden and American Steve Marino, but Lee Westwood pulled his second shot of the day into the lake and started with a bogey six.
Graeme McDowell, however, joined Dyson on two under - and so did Mickelson with birdies at the 12th and 14th.