What's this about the luck of the Irish? Certainly, for Rory McIlroy, there wasn't too much on offer as two double-bogeys on his front nine contributed to a miserable opening round in the Arnold Palmer Invitational for the world number two.

Meanwhile Australian Adam Scott – seeking a third successive win on tour – maintained his stellar recent form to jump into contention again.

On a day when Scott opened with a five-under-par 67 that showcased his short game wizardry as he successfully made eight up and downs, there was a worrying lack of form from McIlroy – just three weeks out from the Masters at Augusta National. He faces a battle to survive the midway cut.

Scott – attempting to become the first player since McIlroy to win three straight starts on the PGA Tour, something the Northern Irishman achieved in his standout 2014 season – was joined on 67 by Henrik Stenson, Marc Leishman, Brendan Steele and Troy Merritt.

But his fellow Aussie Jason Day usurped them to claim the lead with an opening 66.

Day, the PGA champion, muscled his way into the lead with an eagle three on the Par 5 16th and then showed his short game credentials with a sand save for par on the Par three 17th and then made a superb up-and-down on the 18th to claim the first round lead.

Stay patient

“This is early days, I will try and stay patient,” said Day.

It was all so different for McIlroy, who opened with a 75 to lie in tied-106th and well off the pace. Playing in Bay Hill and defending his WGC-Dell Matchplay next week in his only tournaments ahead of the trip to Augusta for the season’s first Major, he had double-bogeys on the first and eighth putting him on the back foot as he turned in 39 before steadying the ship on the journey home.

Although he managed to keep any further doubles off his card, making a fine par save on the Par 5 16th where he put his second shot into the water, McIlroy couldn’t ignite his round and has been left with a lot of work to survive into the weekend.

Graeme McDowell also ran up a big number – a double bogey seven on the sixth – but he still managed to sign for a one-under-par 71.

Seeking to bounce back from a missed cut in the Valspar, McDowell had an up and down round that featured five birdies, two bogeys and a double bogey. The highlight of his round came on the fifth where he holed out a bunker shot for birdie but the joy was short-lived.

He wasn’t alone in having water trouble on the Par 5 sixth, where his second shot plunged into the lake and he ran up a double bogey seven.

Short game

For Scott, it was another good day’s work even if he had to rely heavily on his short game after hitting only 10 of 18 greens in regulation and he was forced to hole a range of par-saving putts.

“I give myself an A for today’s performance,” he said. “I didn’t ball strike it like an A, but I played like an A . . . . I didn’t play my best golf tee-to-green, but I chipped and putted really well today. That’s a nice feeling when you shoot as low as you possibly can.”

Scott, winner of the Honda Classic and the WGC-Cadillac championship on his last two starts, was part of a chasing pack that also featured Stenson, who has recovered from knee surgery to show good form in the run-up to Augusta.

An Orlando resident when stateside, Stenson – edged out by Matt Every last year – said: "I generally have positive memories of my play around here . . . I've had a lot of good tournaments. Of course, there was disappointment not to win last year, but that's the nature of the game. It's not going to be the first or the last time you get disappointed at a golf tournament.

“I’m back here trying to do my best and put myself in a similar situation to where I was last year.”