Lawrie had nine birdies and a bogey in setting the record at the Verdura Golf and Spa Resort.
The record wasn't very old, having been set early in the day by Soren Kjeldsen and matched by Jamie Donaldson and Tano Goya with 65s. They are one stroke off Lawrie's pace.
Six more golfers are at 6-under 66 and 11 more are at 5-under.
Kjeldsen started his round with four pars but then had six birdies, a bogey and an eagle at the par-5, 523-yard 14th hole in setting the record. Donaldson had an eagle at the 568-yard 11th hole and added five birdies while Goya had eight birdies, including four in the row at one point, and a bogey.
But Lawrie grabbed the record for himself. He was 2-under after four holes and made the turn at 5-under after birdies at 7, 8 and 9. He had a birdie at No. 11 but suffered his lone bogey at 13. He got 8-under with three birdies over the span of Nos. 14-17.