Rory needs to turn up the heat after early struggles in Orlando
Rory McIlroy had a disappointing opening round in the Arnold Palmer Invitational at Bay Hill in Orlando.
McIlroy suffered a double-bogey six on the 11th in signing for a two-over-par 74, which leaves him seven shots off overnight leader Emiliano Grillo.
His main problems started after the turn where he took three to get down from the fringe at the 10th before the double bogey on 11.
Having found the water with his approach from the fairway bunker, Ulsterman McIlroy failed to make up and down after his penalty drop, leading to two dropped shots.
He has precious little to take it into today's second round, particularly after his finish which saw him drop a further shot on the 18th.
His approach with a wedge clattered into the rocks short of the green and ricocheted into a greenside bunker, where he failed to save his par.
Tournament host Graeme McDowell started with a bogey at the first, but the Portrush native fought back strongly and had to settle for a level par 72 after lipping out for birdie on 18.
Meanwhile, McIlroy has revealed that he continues to be haunted by his failure to win the 2011 Masters when leading by four shots going into the final round.
Ahead of next month's Masters bid, he said: "Of course, it did sting, of course. I took everything from that day and made sure that whatever I did wrong, I wasn't going to do that again.
"There's a lot of learning stuff in there. But of course it hurt and it still hurts."
World number two Jason Day made a solid start to the defence of his title as course specialist Henrik Stenson found himself in an unfamiliar position.
Day overcame unusually cold conditions to card an opening round of 70 and lie three shots off the early clubhouse target set by Argentina's Grillo.
But Orlando resident Stenson, who has finished in the top 15 in each of his last five appearances in the event, could only manage a three-over-par 75, a score that was matched by American Blayne Barber, a last-minute replacement for Danny Willett after the Masters champion withdrew due to illness.
"Days like this are very difficult," Day reflected. "To start out it was very cold and we were hitting at least 15-20 yards short of our normal number. I'm just glad to get it in at two under.
"Overall I'm very, very pleased with how the first round went."