SOUTHAMPTON, N.Y. – Jason Day has the game to contend in any major championship, and that is true once again this week when he joins 155 other players on Thursday at Shinnecock Hills Golf Club to begin competition in the U.S. Open.

For all his talent, however, he knows that it's all about focus and discipline and having the attitude to want to win more than others who have that same goal. Simply put, he does not lack in confidence.

"I think if I want to be the best player in the world, I'll be the best player in the world," said Day, who ended a 47-week run as world No. 1 early last year. "That's more the mind-set that I have to take. If I want to put my mind to something, I know that there's pretty much nothing people can do about it because if I put my mind to it, it's going to happen.

"But saying that, I know how hard it is to climb that mountain, how hard it is to do the things that I did do, and how much work that you have to actually put into your game to get to that point. Sometimes it can be motivating, and sometimes it can be very difficult to look at knowing that you've got so far to go."

Now ranked eighth in the world, the 30-year-old Day has played in 30 majors entering this week and owns one victory – the 2015 PGA Championship at Whistling Straits. His 13 other top-10 finishes in majors include four runner-up showings, including two at the U.S. Open in 2011 and 2013.

He is 5-for-7 in top-10's at the Open. He said the key to success in the national championship also has to do with the mental side.

"When you come into an event like this, you hear guys moaning and groaning about the setup, or the course we're playing on, how tight things are, or the healthy fescue, or something," he said. "You can kind of write people off straight away if they're complaining."

Day added that he hasn't heard any complaining this week at Shinnecock, a classic William Flynn design that features rather wide fairways, thick rough, and undulating greens.

"A U.S. Open … tests every part of your game and the mental side as well," he said. "So whatever you get, you get. You've just got to kind of suck it up and keep going. I like the stressful part of trying to win a tournament, and I like the stressful part about playing a tough tournament in front of a lot of people and trying to win a major."

Day, who saw Shinnecock for the first time last Sunday, holds two wins this season – the Farmers Insurance Open at Torrey Pines and the Wells Fargo Classic at Quail Hollow – the 11th and 12th of his career.

He will compete against the usual loaded field that includes Tiger Woods, back in an Open for the first time since 2015, and Phil Mickelson, who can complete a career grand  slam this week and purge his memory of his six runner-up finishes in the championship.

Day said he sent Woods a text of Woods in baggy pleated pants.

"He looked like he had MC Hammer pants on," he said. "I'm like, 'Hey man, look at these pants. They're terrible.' It was like old-school stuff. And he didn't text me back."

You know Day will be more fashionably dressed, and focused on contending this week.

"I'm just trying to keep ticking the boxes," he said. "It's been a good start to the year. I know that I feel ready for another major win, and hopefully it's this week."