TROON, Scotland -- On a gorgeous, sunny day along the Scottish coast, the Americans resumed their domination of Royal Troon.

Patrick Reed took advantage of the benign conditions Thursday to start the British Open with a 5-under 66, leaving him one stroke ahead of Justin Thomas and 49-year-old Steve Stricker.

Reed got his round going by holing out from 139 yards at the par-4 third hole for eagle. That sparked him to a 5-under 31 on the much easier outward nine, which generally plays downwind and was especially ripe for going low on this day.

On the return leg, playing tougher holes into the wind, it was all about survival.

Reed managed to shoot even par coming in and had no complaints. Asked to describe the difference between the two nines, he replied, "David vs. Goliath."

After a week dominated by who is -- and, more notably, isn't -- going to Rio next month for the first Olympic tournament in 112 years, it was finally time to put the focus on the sport's oldest major championship.

As usual, the Americans were having their way at Royal Troon, where the last six winners going back to Arnold Palmer in 1962 have been from the U.S.

"I've heard that stat as well, but honestly with how competition is these days, it doesn't really matter where you're from or anything like that," Reed said. "You have to be on your game, you have to stick to your game plan. I think the main thing is to stay with my game plan because the odds of me going out and eagling 3 right out of the gates again, to go and hole out, it's rare."

Then again, the 25-year-old Reed certainly doesn't lack for confidence. Two years ago, he raised plenty of eyebrows by declaring himself to be one of the top five players in the world. That same year, he seemed to thrive on the heckling he received during the Ryder Cup in Scotland.

But Reed has yet to live up to his boasting, leaving him clearly on the outside of a Fab Four that includes Jason Day, Dustin Johnson, Jordan Spieth and Rory McIlroy. They've won six of the last eight major championships and were on nearly everyone's list of favourites coming into the week.

"It doesn't really matter to me. I'm not the one that's writing the articles or doing anything," Reed said. "At the end of the day all I can control is what I do and how I play the game. Honestly, for me, I don't mind flying underneath the radar."

McIlroy, who won at Hoylake in 2014 but didn't play in last year's Open because of an ankle injury he sustained playing soccer with his buddies, got off to a solid start with a 69. He is seeking his fifth major title.

Spieth opened with a 71, one year after his bid for an unprecedented Grand Slam was denied when he missed out on a playoff at St. Andrews by one stroke after winning the Masters and the U.S. Open. Day, the world's top-ranked player and reigning PGA champion, struggled to a 73.

Coming off his first major title at the U.S. Open, Johnson had an afternoon tee time.