Australian Nathan Green holds a share of the lead after the opening round of the Honda Classic at Palm Beach Gardens, Florida.
He and American Michael Connell carded five-under-par rounds of 65, avoiding dropped shots, to edge clear of the field.
Matt Jones is the next best Australian at one under with Aron Price a further stroke back.
Marc Leishman, Nick O'Hern, John Senden and Stuart Appleby all shot 74 to be well down the leaderboard, while Mathew Goggin had a day to forget, carding a disastrous 78.
England's Oliver Wilson is just one shot off the pace, after a bogey-free round of 66 which put him in a group of three sharing third place, with Colombian Camilo Villegas and Brazil's Alexandre Rocha.
Former Masters champion Vijay Singh was a further shot back, with the Fijian at three under, while Northern Ireland's Graeme McDowell and Germany's Alex Cejka stood on two under.
England's Lee Westwood and Argentinian Angel Cabrera, who will return to Augusta next month to defend his Masters title, stayed in touch with the early leaders.
They were both positioned on one under on a congested leaderboard, with Westwood's compatriot Justin Rose on level par.
Padraig Harrington and Rory McIlroy were six shots off the lead after one-over rounds of 71, alongside Chad Campbell, Jeev Milkha Singh and Mike Weir.
Several big names struggled badly, though, with Ernie Els three over after following a double bogey at the short 17th with another bogey at the par-five 18th.
England's Paul Casey was three under after a birdie at the first and eagle at the long third, but his round fell apart on the back nine with four bogeys and a double bogey, and he went to the clubhouse at three over.
Sergio Garcia also had an unsatisfactory round, with three birdies on the front nine countered by seven dropped shots in his round, and he was ailing on four over.