At 8-1 odds, he is the co-favorite with U.S. Open champion Dustin Johnson to prevail this week at Royal Troon. There's a spread of outstanding talent at the top of golf at the moment and anyone of them can go on one of those runs that McIlroy, Spieth, and Day enjoyed before DJ had his turn. That should put to rest three days of consternation about another tournament - the Olympics - that doesn't have almost the history or the tradition of golf's oldest championship.

But the world number seven is keen to take what could be a once-in-a-lifetime opportunity given that golf's Olympic future beyond 2020 will be decided next year.

Then came this velvet-hammer subliminal message from McIlroy: "I've got four major championships, and I'd love to add to that tally, just as those guys would love to add to their one or two majors that they have and just keep going".

Jason Day walked away from a loss in the British Open at St. Andrews previous year more motivated than ever to win his first major.

"Welcome to the 145th Open Championship".

The 38-year-old is turning in the best season on the PGA Tour for any player who has not won a tournament.

But, while Spieth said Tuesday it was "probably the hardest decision I've ever had to make in my life", McIlroy was much more cavalier about skipping the Olympics. "And to reach a third leg of the Grand Slam this week would be a fantastic achievement".

Even so, his level of comfort was never more evident, particularly when he finished his 20-minute news conference.

The last Open to be held at Troon was in 2004, when the completely unheralded Todd Hamilton came away as the champion golfer.

In 1997 the victor was Justin Leonard, a Texan just like Spieth.

Getty Images 6 Oosthuizen chats with caddie Greg Hearmon as he reflects on his hole-in-one

The mystery is Royal Troon, a links Johnson had never seen until he arrived after a weekend in Ireland.

The wind was into his face on Saturday and Sunday on the easier opening holes, and the prevailing wind at his back returned the following three days.

Jason Day and Dustin Johnson are favorites this week at The Open, but bettors and bookmakers both overseas and in Nevada agree that the tournament at blustery Royal Troon is wide-open. While it only features one bunker ahead of the raised green, its stretched shape hooks right just before being flanked by thick gorse bushes on the left side and the railway for which it is named on the right. Fairway bunkers effectively are a half-shot penalty, possibly a full shot or more if the ball rolls up against the vetted faces. Not the two-shot penalty on the final hole of the 2010 PGA Championship for grounding his club in a bunker ("I still don't think that was a bunker", he said).

Dustin Johnson tees off on the second hole during the final round of the Bridgestone Invitational golf tournament at Firestone Country Club in Akron, Ohio. Right now I feel like I've got to do a little more work throughout my swing to get it compact and ready for this style of golf. Troon is a historic venue with all the characteristics you would expect from an Open and a Scottish links test.

That's 12 fewer than what is believed to be the highest score in major competition at Troon's eighth, suffered by German amateur Hermann Tissies in the 1950 Open.

McIlroy has been feisty this week.

McIlroy, who leads a host of the sport's biggest names to have withdrawn in controversial circumstances from next month's Rio Olympics, is bidding to win his fifth major and second Open after his victory at Hoylake in 2014.

No. 4-ranked McIlroy, 27, owns 19 worldwide victories, including four majors.

" That being said, I felt for me it was going to be a great experience and possibly once in a lifetime". Two times more money had been bet on Day to win the tournament than any other golfer at the SuperBook, as of Tuesday afternoon.

"I hit driver on one, maybe on two, just depending, and then on three for sure and four".