Lamprecht, six foot eight inches tall, mixed seven birdies with two bogeys to move to five under par, two shots clear of American Stewart Cink.
"It's pretty surreal," Lamprecht told reporters. "It's nice to see a lot of work behind the scenes pay off. It's something I haven't dreamt of yet, but it's pretty cool."
Cink, Open champion in 2009, rolled back the years with a flawless 68 to finish at three under, one ahead of his compatriot Jordan Spieth who began his bid for a second Open title with a 69.
German Marcel Siem made four birdies on the front nine to get to three under along with local favourite Tommy Fleetwood who is bidding to become the first Englishman to win the Open since Nick Faldo in 1992.
England's Matthew Jordan, given the honour of hitting the opening tee shot at Royal Liverpool Golf Club where he has been a member since the age of seven, carded 69.
"Amazing, I'm kind of running out of words to describe it," the 27-year-old told reporters. "It was crazy, mental, loud, everything that I could have wished for."
"I'm certainly trying to think of a better experience than that and I don't think I can."
World number one Scottie Scheffler made a slow start to his bid for a first Open title, slipping to one over after 14 holes, level with Australian Cameron Smith who mixed four bogeys with three birdies early in his title defence.
World number two Rory McIlroy, favourite to win his fifth major at the course where he lifted the Claret Jug in 2014, was among the late starters alongside his Ryder Cup team mates Jon Rahm and Justin Rose.
