Kevin Kisner of the United States leads the way after the first round of the British Open on Thursday, but Rory McIlroy is one of the big names who got their bid for the Claret Jug off to an encouraging start at Carnoustie.

Kisner went out in one of the first groups just before 8am (0700 GMT), yet his five-under-par round of 66 was not beaten all day as reigning champion Jordan Spieth and other big names struggled to properly get to grips with the Scottish links.

That means Kisner is a shot clear at the top of the leaderboard.

“The golf course is great for me,” said the 34-year-old, who led going into the final round of last year's PGA Championship before finishing tied for seventh.

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“Going forward, you never know what you're going to have in Scotland. I know the rain is coming in tomorrow,” added Kisner, who is sharing a house with Spieth and several other US stars this week.

Kisner had an eagle and four birdies in his round on a perfect summer's day on Scotland's east coast, and he leads from compatriot Tony Finau and the South African duo of Erik van Rooyen and Zander Lombard, who all went round in 67.

Another South African, Brandon Stone, joined American pair Ryan Moore and Brendan Steele in shooting a three-under 68, while McIlroy lurks ominously after a two-under-par round of 69.

Back at the course where he was the best amateur as a fresh-faced teenager the last time The Open came here in 2007, the Northern Irishman adopted an attack-minded approach and had just one dropped shot all day, at the par-four fifth hole.

“I got away with some tee shots, but at the same time, I think that's what I have to do. That's my game plan this week. I'm convinced that that's the way that I should play it. It's not going to be for everyone, but it worked out pretty well today,” said McIlroy, who is looking to end a four-year major drought here.

McIlroy will be one of the earliest starters on Friday, going out at 7:52am, a full five hours before Kisner begins his round.

PGA champion Justin Thomas and Zach Johnson, the 2015 Open champion, are also two-under, along with former Masters champion Danny Willett and Spain's Jon Rahm.

Woods not discouraged

Meanwhile, Tiger Woods was not discouraged as he began his bid to finally land another major by shooting a level-par round of 71.

Now 42, Woods is being tipped by many to contend for the Claret Jug here, 10 years after he last won a major at the US Open.

Woods reached the turn two-under but, hindered by a neck problem, he dropped three shots in an often erratic back nine and has work to do on Friday.

“I got off to a great start. I birdied one and birdied four, and I was right there,” he said.

“I had an 8-iron to six and was looking like I could really do something here. Unfortunately, it didn't quite turn out that way, but part of this afternoon wave, I was one of the lower rounds.”

Americans have won the last five majors, including Spieth's victory at Royal Birkdale 12 months ago. However, his defence of the trophy did not get off to the best start, as a poor finish to his first round saw him conclude the day one-over after a 72.

He went to the 15th tee three-under, only to drop three shots on the next two holes. He then drove into the Barry Burn on the 18th -- scene of Frenchman Jean Van de Velde's infamous final-day meltdown in 1999 -- and ended with another bogey.

“It felt like a missed opportunity. I felt like I was really going well,” said the Texan, who hopes that a turn for the worse in the weather forecast for Friday will spark an upturn in his fortunes.

“I think I'm certainly in a recoverable situation. I mean, I imagine this is as easy as the course could play.”

As the prolonged summer heatwave continued on Scotland's North Sea coast, world No.1 Dustin Johnson was one of those who had an afternoon to forget.

He shot a five-over-par 76 and faces a struggle to make the weekend, with weather conditions set to deteriorate on Friday.