Rory McIlroy five off Bay Hill pace after final-hole double bogey
Rory McIlroy suffered a frustrating finish on day one at the Arnold Palmer Invitational after a final-hole double bogey left him five off the pace.
The Northern Irishman didn't drop a shot in his first 17 holes as he moved to five under but drove out of bounds at the last as he carded a 69.
McIlroy's round matched compatriot Graeme McDowell's earlier 69.
Henrik Stenson led on eight under after a 64 which left him a stroke ahead of US duo Aaron Wise and Talor Gooch.
Jimmy Walker and Rickie Fowler were in a group sharing fourth place on five under.
Of the other Irish players, Padraig Harrington fired an opening one-under 71 but Shane Lowry struggled to a 75.
After a birdie at the first, McIlroy holed a 12-foot par putt on the third before a run of three straight birdies from the sixth was followed by another gain at the 10th as he moved to five under par.
However, the former world number one's ball-striking became erratic as he had to scramble pars on a number of holes before a hooked tee at the last went out of bounds.
After a promising start to this 2018 campaign in the Middle East, McIlroy has struggled in his four tournaments in the US.
He has missed the cut in two of his PGA Tour outings - including last week's Valspar Championship - and his best finish in those four events was a share of 20th place in the Genesis Open at Riviera.
Tiger Woods continued his return to form on his latest comeback after firing a four-under-par 68 on Thursday - which included a double bogey.