Shane Lowry made a flawless start to his bid for a second Open title as Rory McIlroy effectively wrote off his chances of doing the same at Royal Troon.
Lowry carded five birdies in a bogey-free 66 that was only surpassed at 9.33pm by England’s Daniel Brown, the world number number 272 returning a brilliant 65 to claim a shock lead on his Open debut.
Brown, who won his maiden DP World Tour title in Northern Ireland 11 months ago, took advantage of calmer conditions for the later starters to birdie the third, fifth, 10th, 11th, 16th and 18th.
“I’m very excited but you have to keep your feet on the ground,” said the 29-year-old from Northallerton, who finished 61st in the Scottish Open on Sunday after a run of six missed cuts and a withdrawal in his last seven starts.
“I am just going to try and go out and do the best I can.”
The contrast between Lowry’s 66 and the 78 of McIlroy immediately brought to mind the 2019 Open at Royal Portrush, when Lowry started with a 67 on his way to the Claret Jug and McIlroy’s chances were blown away with a 79.
“I’m pretty happy, but it’s only one day,” Lowry said. “We’ve got three more days.
“I kept telling myself that out there because for some reason I felt like the crowd were getting very excited. It was late in the afternoon and a few pints of Tennent’s were had out there. It felt more like the weekend.
“I just kept on telling myself there’s a lot more to do so I just kind of stayed in my lane and hit some good shots, and I was pretty happy with how I handled myself.
“The walk down 18 was actually pretty cool. I said to Billy Foster (Matt Fitzpatrick’s caddie) that it’s the greatest walk in golf and I got to do it on a Sunday afternoon with a full house. That’s the plan, to try to get to do that again.
“I’d give anything to win this tournament again. I’d give anything to give myself a chance to win this tournament again and that’s why I’m here this week.
“No matter what I do that week in Portrush will always have a special place in my heart. I love that place and I love this tournament.”
A downbeat McIlroy had earlier dismissed his chances of mounting a challenge for a fifth major title after a costly run around the turn.
McIlroy was level par after seven holes before running up a double bogey on the signature par-three eighth, the Northern Irishman’s first attempt to escape a bunker on the Postage Stamp coming back to his feet.
With the back nine playing downwind McIlroy was hopeful of repairing the damage, only to drive out of bounds on the 11th to run up another double bogey and eventually finish seven over par, 12 behind his great friend Lowry.
According to statistician Justin Ray, lead data analyst at KPMG Performance Insights, 87 per cent of Open winners since 1960 have been within four shots of the lead after the first round.
Asked if he could make up the ground he had conceded, there was a lengthy pause before McIlroy said: “I mean, all I need to focus on is tomorrow and try to make the cut. That’s all I can focus on.”
The 35-year-old, who agonisingly missed out the US Open title last month, added: “I felt like I did OK for the first part of the round and then missed the green at the Postage Stamp there and made a double.
“Even though the wind on the back nine was helping, it was a lot off the left. I was actually surprised how difficult I felt like the back nine played. The conditions are very difficult in a wind that we haven’t seen so far this week.
“I guess when that happens it starts to present different options and you start to think about maybe hitting a few clubs that you haven’t hit in practice. Just one of those days where I just didn’t adapt well enough to the conditions.”
Bryson DeChambeau, who edged out McIlroy at Pinehurst to win his second US Open, also found himself well down the field following a 76, although the American did at least hole from 55 feet for an eagle on the 16th.
DeChambeau’s front nine of 42 included a double bogey on the 612-yard sixth, where he could only advance his second shot a few yards from heavy rough before hitting his next onto the adjacent 13th fairway.
Thomas had set the early clubhouse target on three under par thanks to birdies on the 17th and 18th, the two-time major winner’s 68 representing a 14-shot improvement on his opening round at Hoylake last year.
“I couldn’t even tell you what I was thinking or how it was then,” Thomas said when asked to compare the two rounds.
“I’m just worried about how I am now, and I’m very pleased with my game and know things are continuing to work in the right direction.”
Former supermarket delivery driver Joe Dean was part of a seven-way tie for fourth place on two under par which included US PGA winner Xander Schauffele and Ryder Cup team-mates Nicolai Hojgaard and Justin Rose.
Rose, who had to come through a 36-hole qualifier to make it to Troon, carded two birdies and 16 pars in a bogey-free 69.