It's supposed to be the toughest test in golf, but it could be a real grind with the ugly yet familiar spectre of slow play rearing its head again at the US Open this week, with Padraig Harrington preparing himself for “the slowest rounds of golf ever in tournament golf” in LA.

The quirky layout at Los Angeles Country Club should lead to some good viewing, but it could be a long stint in front of the TV for golf fans and a long day for the players if Harrington’s assessment is correct.

With a mix of par 5s that can be reached in two and some drivable par 4s, coupled with two of the longest par 3s ever seen in the US Open, there could be a few hold-ups in the first two rounds – and Harrington is prepared for a marathon.

"I need to manage myself," Harrington told the Irish Independent. "This is going to be an extraordinarily long week. These are probably going to be the slowest rounds of golf ever in tournament golf. I'd be surprised if they're under six hours.

"There's just a lot of crisscrossing. There's just a lot of holes where people and when plays slow and crisscrossing, everybody’s 'Oh, no, you go ahead. No, you go ahead. No, you go.' Because they all know they're going to be waiting for them at the next tee.

"When you have the drivable par-4s and reachable par-5s, that all slows play down because they're reachable, but you're still taking fives.

"It's not like they're straightforward in any shape or form. So yeah, this is going to be a long day on your feet all week. So the one thing I have to manage is that I'm fresh for the whole week for Sunday."

The three-time Major champion says the course is “set up for four under par” to be the winning score, and he’d personally “give up body parts for four under par” and see what that gets him come Sunday evening.

Harrington looking forward to Mickelson pairing

The 51-year-old will play alongside Keegan Bradley and Phil Mickelson in the first two rounds of the US Open, and says he’ll enjoy his time chatting to Mickelson in particular.

"We get on well, we've known each other for years, and there'll be a little bit of competition between us,” said Harrington. “He'll be trying to out-drive me, and we both have good short games and will certainly need them here.

"We've chatted a lot and will talk a lot. And as I said, you do tend to play better when you're in familiar company, and you're having a bit of a chat, and you're enjoying yourself.

"So there should be some nice distraction. And there's a lot to talk about, too. And a lot going on. So yeah, I consider it an excellent draw for me, yes."

Harrington played alongside Mickelson at Kiawah Island three years ago when Lefty won a sixth Major and become the oldest player to win one of golf’s big four – could there be a strange twist of fate where the Irishman now goes on to claim that mantle?

"Well, I'd like it to work like that. But we play well together.”

Despite his advancing years, Harrington maintains that competitive edge and still thinks he could challenge for a fourth Major as an eternal optimist: "That's my personality. And that's my burden."

Harrington's credited a stellar start to his PGA Tour Champions career to help reignite that competitive spark - winning the US Senior Open as one of four victories in his debut campaign.

And this season has five top 10s in six starts including losing a playoff for the Senior PGA Championship - while on the regular tours he made the cut at the PGA Championship, got a top 10 at the Texas Open on the PGA Tour and finished fourth in Abu Dhabi on the DP World Tour.