Rory McIlroy and Seamus Power were the Irish pacesetters on day one of the 151st Open Championship at Royal Liverpool, where amateur champion Christo Lamprecht is in a share of the lead.
Roared on by a partisan crowd, local Tommy Fleetwood carded an opening 66 to share the clubhouse lead with South African Lamprecht and Argentina's Emiliano Grillo on five-under par.
Antoine Rozner, Adrian Otaegui and Brian Harman were all a shot behind, with former champion Stewart Cink - who denied Tom Watson a fairytale victory in 2009 - part of a group on three under, which included US Open champion Wyndham Clark.
McIlroy endured a frustrating start to his latest quest to reclaim the Claret Jug with a mixed round featuring three birdies and three bogeys.
It might even have been worse after he found a greenside bunker at the par-five 18th and needed two shots to escape the sand trap.
Yet he held his nerve to save par from 10 feet and keep himself within five strokes of joint-leaders Tommy Fleetwood, Emiliano Grillo and Lamprecht.
"You are just hoping to make par somehow and get out of there," said McIlroy of the final hole.
"I got lucky because that ball could have gone into a deeper part of my footprints and I could have been there all night. It was a really good par in the end.
"I was probably hoping for a bit more at the start of the day but, overall, two over through 12 - to get it back to even for the day, I'm pretty pleased with that.
"I could have let that round get away from me but I didn't with the two birdies on the back nine."
Power carded 14 pars en route to a steady 71. The Waterford native, whose best major finish was tied ninth at last year's PGA Championship, birdied the par-fives at the fifth and 15th, cancelled out by back-to-back bogeys at six and seven.
Shane Lowry endured a frustrating finish, with bogeys at 13 and 15 as he posted a one-over round of 71.
The 36-year-old, who finished in the top-10 at this venue in 2014, began strongly with an opening birdie. He reached the turn at even par, with another birdie at four, mingled with dropped strokes at the third and ninth.
He clambered back under par with a eight-foot putt for birdie on 11 but there followed a messy stretch in the middle of the back nine, wild driving costing him at the short 13th and then the long 15th, having plunged both the shots into the rough.
Meath amateur Alex Maguire, who booked his place in the tournament after winning the St Andrews Links Trophy, is just a shot behind McIlroy and Power on one over.
The 22-year-old finished strongly with birdies on the par-fives at 15 and 18.
Maguire told RTÉ Sport his day was one to treasure but also tinged with regret: "I felt like I played a lot better than that. I hit it really well off the tee. I was in a lot of fairways and hit a lot of greens. I made a mental mistake on 14 when I pulled out driver after a few good drives. That's a hole where you can't hit driver. I hit in into a bunker and I had one bad swing from there which led to a costly six.
"I felt like I was playing great the whole way around. It was nice to finish up the way I did birdieing the two par fives on the way back.
"It was a great up and down on 17 as I was caught in the bunker shot and hit it to within a few feet. I'm proud of myself for sticking in there and getting close to level par. It stings a little bit with that tee shot on 14.
"I have high standards and I feel tomorrow I could go out there and hit a score under par. The way I played today I could definitely do it if I holed a few putts. I'll go out tomorrow at around noon and keep committing to the process and committing to shots. If I make the cut great, if not I can at least go home with my head held high."
Maguire is familiar with Lamprecht from his amateur career and was delighted to see him do well, even if it is likely to cost him a chance at the silver medal.
"We played the last two practice holes on Tuesday. I was on my own and him and Brandon Grace came up and 17 and we played the last two holes. But I actually met Christo years ago when he won the East of Ireland. He came over to Bettystown and one of the members knew one of the head coaches in South Africa. They brought the guys over and we played a Senior Cup match against them.
"I played with Christo that day and he drove to the fifth green in Bettystown which is like 350 yards.
"So I was very impressed by what he was doing. In the last five or six years he's become such an amazing player and at the British Amateur I was delighted to see him win.
"It's no shock he's at the top of the leaderboard to be honest. He hits the ball miles. I wished him the best of luck this morning and I think he's doing OK at the moment!"
2011 champion Darren Clarke carded an opening 73, while two-time winner Padraig Harrington battled his way to a three-over 74 after a horrible stretch in the front nine when he went bogey, bogey, double-bogey between the fifth and seventh.
The Dubliner recovered with back-to-back birdies on 13 and 14, keeping him in with a decent chance of remaining around for the weekend.
