Padraig Harrington leads the Irish challenge at the Arnold Palmer Invitational.

The three-time Major winner enjoyed a bogey free opening round at Bay Hill as he carded a 4-under par 68 that leaves him just two shots behind out-right leader Morgan Hoffmann.

World number one Rory McIlroy is on 2-under par, while Graeme McDowell finished the day on level par.