PHIL MICKELSON told a journalist to "let it go" in frustration at being asked LIV Golf-related questions after his opening round at the Open.

Mickelson's absence from past champions' events at St Andrews was one of the main talking points in the build-up to the 150th edition of the championship this week.

The 2013 winner insisted he was invited to the celebratory dinner and four-hole exhibition tournament but, having become one of the faces of the controversial Saudi-backed rival LIV series, declined to avoid becoming a distraction.

This differs from the stance taken with LIV figurehead Greg Norman, the Open champion in 1986 and 1993, with organisers the R&A making abundantly clear the Australian had not been invited.

"The R&A contacted me a couple weeks before and said, 'Look, we don't think it's a great idea you go, but if you want to, you can'," Mickelson told reporters after beginning his latest Open challenge with a level-par 72.

"I just didn't want to make a big deal about it, so I said, 'fine'. We both kind of agreed that it would be best if I didn't."

Asked if he was sad to be in such a position, the 52-year-old said: "No, no. Not at all. I think that I couldn't be more excited and ecstatic with where I'm at.

"I love the events. I get to have golf in my life and competitive golf in my life on a scale that is fun, exciting, different, and lets me play and compete but still do the things outside that I want to do."

Pushed further on missing the dinner, which was attended by the likes of Jack Nicklaus, Tom Watson, Sir Nick Faldo and Tiger Woods, Mickelson snapped: "Let it go, dude. Let it go. That's three times you've asked the same question.

"I don't know what to tell you. I couldn't be happier."

Mickelson insisted he had no regrets about signing up for the big-money LIV circuit, which has sparked a huge row in the game and led to him being banned from the PGA Tour.

The American said: "I made the right decision for me and I'm excited about having the opportunity to play competitive golf and have it in my life in a more moderate scale to where I can do some things outside of that too. I freed up a lot of other time as well.

"I couldn't be happier. I think it's been really good. I can't wait to get to New Jersey and play another event there."

Woods this week criticised LIV players for having "turned their back on what allowed them to get to this position". He also denounced the 54-hole format of LIV tournaments.

Mickelson said: "I certainly respect his opinion. I have a lot of respect for him. I think everybody's going to have strong emotions and opinions about it, and I certainly respect his."