Justin Rose tucked himself in just three strokes off the lead when the Arnold Palmer Invitational began at Bay Hill.
American Jason Dufner and Korean Charlie Wi were the pace-setters with six under par rounds of 66.
Tiger Woods, recovered from the ankle injury which led to him pulling out of his last US PGA Tour event a fortnight ago, is a six-time winner of the title and ominously placed alongside Rose.
Rose, winner of the WGC-Cadillac Championship in Miami on the same day that Woods quit after 11 holes, is trying to make it four European victories in a row in the States.
He was one over after five, but sank a 22 foot putt on the 15th and then had three more birdies in four holes from the fourth.
If he can win again Rose would go to a career-high fourth in the Official World Golf Ranking behind Luke Donald, Rory McIlroy and Lee Westwood.
Round in 71 playing with Woods was Ernie Els, who needs a top-three finish to have a chance of climbing into the world top 50 in time for the Masters Tournament.
Els, who blew last week's Transitions Championship with two closing bogeys, started with ten successive pars, then had a hat-trick of birdies to move into contention.
Going in the water on the 555 yard sixth led to a six and he then dropped another shot at the eighth.
Scot Martin Laird began his title defence with a level par 72, the same as Graeme McDowell and Sergio Garcia, while Ian Poulter had a 71.
