Rory McIlroy admitted the electric atmosphere was “unbelievable” and Shane Lowry confessed to getting “goosebumps” as they enjoyed mixed days in the opening round of the Men’s Olympic Golf Competition in Paris.

McIlroy made an eagle and five birdies at Le Golf National but even after three-putting the last for his fourth bogey of the day and signing for a three-under 68 that left him five shots behind Japan’s Hideki Matsuyama, he wasn’t pressing any panic buttons as he bids to add to Ireland’s medal haul.

“It was okay,” McIlroy said. "Solid start. A bit up-and-down which is to be expected. I didn't do a whole lot between The Open and here. Some good. Some not so good. A solid opening round. A little disappointing with the three-putt at the last. Overall, as I said, a solid start and something to build upon."

Lowry got such a big cheer from the Irish gallery on the first tee that he found it “off-putting” and started with a bogey after pushing his tee shot into the rough.

He recovered with birdies at the third, fifth and 14th but while he bogeyed the 15th and 18th for a 71 that left joint 42nd in the 60-man field on level par, he pointed out that “a lot can happen between now and Sunday evening.”

“I feel like it's probably the worst score I could have shot which is very frustrating,” the Offaly man said.

“I feel like I'm a long way behind third at the minute, but golf's a funny game, and it can only take a good nine holes to get yourself back in the mix.”

Early morning rain softened the course, and former Masters champion Matsuyama took advantage, reeling off eight birdies in a bogey-free 63.

He led by two strokes from PGA and Open Championship winner Xander Schauffele, the reigning Olympic champion, and by three from Chile’s Joaquin Niemann, Argentina’s Emiliano Grillo, and South Korea’s Tom Kim.

World number one Scottie Scheffler shot a four-under 67 to sit in an eight-way tie for sixth alongside the likes of former number one Jon Rahm and England’s Tommy Fleetwood.

Play was suspended twice due to the threat of lightning but there was plenty of human electricity in the gallery too.

“I thought the weekend it might get a few more people,” said McIlroy, who followed a bogey at the second with birdies at the third and fifth before hitting a 278-yard five-wood to five feet to set up an eagle at the ninth to turn in 33.

“I thought the first couple of days might be a little bit quieter, but it was awesome. Tokyo was a ghost town. This was much better.”

He bogeyed the 10th and 12th to slip back to one-under but made three successive birdies from the 13th to move into the top 10 before blasting his 37-foot birdie putt 15 feet past at the 18th and missing the return to sign off with a bogey that left him tied for 14th.

“I think the crowd support that we all got out there was amazing,” McIlroy said. “Obviously, there were a few more flags and a bit more, I don't know what the word is, like nationalism. But we were all really well supported out there. It was great to see.”

Lowry so badly wants to add to Ireland’s medal haul and he admitted he was taken aback by the roar he got on the first tee.

“It was nearly off-putting a little bit, like wow, I wasn't expecting that, and I got goosebumps and I hit a really bad tee shot,” said Lowry, who watched Daniel Wiffen win gold on Wednesday and admitted to feeling “major butterflies, nerves, anxiousness” as he headed to the tee. “But I'm not blaming them. It was my fault.”

He added: “I want to add to the tally of medals for my country. I have a long way to go to do that. Maybe I wanted that too much today. Hopefully, tomorrow I shoot a better score, but overall, it's been pretty good.”

Meanwhile, Sweden’s Joakim Largergren put Sunday’s runner-up finish to Conor Purcell in the NI Open behind him by opening with a nine-under 63 to lead the Irish Challenge at The K Club’s Palmer South course.

He led by a shot from American Aman Gupta and Sweden’s Oliver Gillberg, with the host club’s Liam Grehan, the best of the 14-man Irish contingent, tied for eighth after a 67.

Kinsale’s John Murphy and Kilkenny’s Mark Power were 21st after 69s but Galgorm winner Purcell struggled to a 75 to share 133rd with Gary Hurley.