OAKMONT, Pa. — Jason Day has a cold.

This is not bad news at all for the No. 1 golfer in the world and reigning PGA champion as he heads into the U.S. Open on Thursday. He actually is on the back end of it, he said.

Plus, he has had much worse, notably the case of Benign Positional Vertigo that caused him to collapse at the U.S. Open last year. What’s more, the sniffles ratchet up the stress and Day said, “I feel like I thrive under stress.”

StoryU.S. Open 2016 tee times

So, all told, he is in a good frame of mind, and decent health, as he prepares for the major championship for which he believes he is best suited. “I mean, this is one tournament that is very stressful,” he said on Tuesday.

“I’ve always said, since I started playing major golf, you come in to major championships and your attitude has to be on point,” Day said. “If you’re going to have a bad attitude, you may as well not even tee it up that week because you probably won’t play good anyway.”

In other words, he is not grumpy in the manner of the famous singer who declined to be interviewed for author Gay Talese’s classic profile, “Frank Sinatra Has a Cold.” Day explained that he told a TV interviewer about his upper respiratory infection the other day only because he likes to be totally honest. “This shouldn’t be a ‘News and noteworthy.’ It’s not an excuse. I’m going to be ready for the start Thursday,” he said.

advertisement | advertise on newsday

Day was stunningly ready for the finish last year at Chambers Bay, despite having to lay down in the grass during the second round with an unknown ailment later diagnosed as vertigo. He did not pull out of the championship before the next round. Instead, he finished Saturday leading the Open before falling into a tie for ninth.

By hanging in there, he proved something to himself, maybe more than he did by earning his first major championship win at the PGA two months later.

“There were a few spots out there where I thought I was going to quit, just go, ‘I’m done with it because I can’t handle it anymore.’ I felt like I was going to throw up and I just felt ill,” he said, recalling the weekend at the U.S. Open.

@Newsday

“Obviously, it was more of a mental barrier that you’ve got to break through when you have certain things like that go on. You’ve got to keep pushing, keep pushing. It didn’t work out my way on the last day — I kind of pushed myself a little bit too much. But yeah, it was great. It was a good experience for me to really understand how far I can push myself.”

He is pushing himself in a different way now that he has that No. 1 ranking. He insists he is no less hungry than before he finally became a major champion after numerous close calls. “I’ve never been more stressed in my life than right now. It’s just because being No. 1 in the world, having a lot of expectations on you, having to practice so hard to keep that No. 1 spot,” he said, “trying to win as many tournaments as you can puts a lot of stress and pressure on your shoulders.”

Which is all fine with the man who co-stars in a commercial starring his 3-year-old son, Dash. The toddler is quite the motivator, Day said, telling his dad before every major, “Make sure you win because I want to kiss the trophy.”

“I don’t know if that adds more pressure on me or not,” the top player said. “But it’s great.”