PACIFIC PALISADES, Calif. — The focus, of course, is on the golf. Always golf first. It is their living, after all.

But some PGA Tour players, more specifically many of those from Australia, sometimes have an eye on another sport they grew up with — rugby — while they’re in the midst of tournament play.

While rugby is on the outer ring of the fringe-sport category in America, it’s about to make a big splash in the U.S. in two weeks when the National Rugby League (NRL) plays two of its opening-day matches at Allegiant Stadium in Last Vegas, where the Super Bowl took place last Sunday.

On March 2, the Manly Sea Eagles play the South Sydney Rabbitohs and the Brisbane Broncos play the Sydney Roosters in a doubleheader to open the NRL season — much in the same model as the NFL has marketed its product outside the U.S. with regular-season games.

For the NRL, this is the first time it’s being done, and a couple of the PGA Tour stars playing in this week’s Genesis Invitational at Riviera have taken notice.

Jason Day, who shot a 2-under-par 69 in Saturday’s third round to get to 10-under and four shots off Patrick Cantlay’s lead entering Sunday’s final round, has a long history with the Brisbane Broncos, because his late mother, Adenal, was a rabid fan.

“My mom used to watch it all the time and we would sit there and watch it with her,’’ Day told The Post. “And if they were playing bad, she’d swear at the TV and turn it off and then no one could watch the TV. Funny enough, I’m starting to do that as an adult. If my team over here [in America], the [Cleveland] Browns, are playing badly, I shut it off and no one’s allowed to watch TV.

“So,’’ Day continued with a laugh, “I’ve turned into my mom.’’

Day recalled his days as a youth following the Brisbane Broncos because they were his mother’s favorite.

“I am definitely a Broncos fan,’’ Day said. “I grew up watching them back in the day of Gorden Tallis, Shane Webcke and Darren Lockyer and a lot of those guys. That’s from the old Broncos days I remember watching. Sometimes it was watching a full game and sometimes it was done in 10 minutes [depending on his mother’s mood].’’

Day said, “I still look at the ladder [standings] to see how the teams are doing, but it’s difficult to watch the matches live because of the time difference.

“I’ll typically watch highlights on YouTube,’’ he said.

Adam Scott was born Adelaide, grew up a fan of Australian Rules Football (AFL), and later became a fan of NRL. He’s intrigued by the doubleheader in Las Vegas and what it does for the league.

“When I moved north when I was seven, I started getting into Rugby League and the Broncos,’’ Scott told The Post. “Those were the dream years of the Broncos around that time, when they were great. They had absolute legends playing for them at that time, so it was a great time to get into Rugby League.

“I see this [Las Vegas] along the lines of the NFL playing a game in London,’’ Scott continued. “It’s marketing, really. It can be a spectacle for sure, and it’s good for all the Aussies over here. Maybe they’ll get the chance to go and watch.

“I think that what you get out of all this, whether you’re an Aussie watching the NFL or an American watching Rugby, you can appreciate all the athletes in these sports. Hopefully, they see some pretty good athletes playing hard, hitting each other pretty hard.’’

Day said he’s fascinated by the NRL’s international foray into Vegas.

“Once the American viewer gets to experience NRL, especially in Vegas, which is kind of a unique experience for people, I’m hoping it gains traction over here and gets bigger,’’ Day said. “If you take to the Premier League, for example, soccer is a very big sport around the world, but it wasn’t huge like it is today in the United States. It’s massive now, with MLS.

“That’s what the NRL is trying to get a hold of. Like the fan bases over here, if you get enough people into the sport, then it just opens up another avenue, certainly revenue for NRL, but also a different type of fan base that could open up potential more travel to the U.S.

“It’s definitely great exposure,’’ Day went on. “It’s like the NFL going to Europe and South America to try to build a new base of fans. It’s essentially what the NRL is trying to do. America is very driven by sports. That’s one thing that’s great about this country — the culture over here is very sports driven. We watch a lot of sports. There’s always some type of sports on TV every night.

“This will be good exposure for the NRL to have the teams come across to America.’’