Towering amateur Christo Lamprecht has roared to the top of the leaderboard on the opening morning of the 151st British Open as the unlikeliest of early contenders for Cameron Smith’s crown.

Smith launched his defence of the title he won at St Andrews in grand manner at Royal Liverpool with an immaculate birdie at his opening hole, but had to negotiate some adventures in the rough and sat at one over after 13 holes in what looked like the most benign of conditions after a wet and windy week.

Meanwhile, 22-year-old South African Lamprecht, a Georgia Tech student who qualified by winning the Amateur Championship 30 miles north at Hillside last month, was walking tall, shooting a five-under par 66 to lead the early wave by two shots from 50-year-old 2009 champion Stewart Cink.

Lamprecht, who stands at 203cm, fired seven birdies in his round, including three in his first six holes and finishing with a short birdie putt at the last after reaching the par five in two.

After local player Matthew Jordan had enjoyed the “amazing honour” of hitting the championship’s opening tee shot and went on to shoot an impressive 69, Lucas Herbert kicked off the Australian challenge in fine fashion.

But when joint leader with Lamprecht at three under, the Victorian had a nightmare at the new, short 17th hole, making a triple-bogey six after missing the green, chipping into pot bunker and failing to extricate himself first time.

All eyes were on Queenslander Smith, as he was introduced at the first tee as the defending champion to a warm reception from a full-house surrounding the hole and the odd cheer of ‘C’mon Aussie’.

He didn’t let them down with a drive straight down the middle, an approach from 160 yards to 12 foot, and a putt that never looked as if it was going anywhere but the centre of the hole.

But he then struggled his way around, finding more than his fair share of bunkers and heavy rough as he mixed three birdies with four bogeys in his opening 11 holes.

Queenslander Smith has pronounced himself confident of his chances, saying he’s a better golfer than when he lifted the title at St Andrews last year as he seeks to become the first Australian back-to-back winner since the great Peter Thomson, who was the last man to win three in a row between 1954 and 1956.

Adam Scott, who celebrated his 43rd birthday at the weekend, was leading the early Australian challenge, going through 13 in one under.

The 27-year-old Jordan, who’s been a member at Royal Liverpool since he was seven and came through qualifying to earn a place in the 156-man field, enjoyed a rapturous welcome from family, friends and local supporters.

“Amazing, I’m kind of running out of words to describe it. It was crazy, mental, loud – everything that I could have wished for,” he said.