It was the latest in a series of thrilling moments at one the developmental tour's most notorious shootouts.
'Anytime you shoot a 60 you're going to make some putts,' said Thompson, who also made a long birdie putt at No. 8, his second-to-last hole. 'I couldn't be happier with the way I played and I'm even happier with the way I putted.'
This is the tournament where Jason Gore shot a 59 in the second round in 2005, the year he earned his battlefield promotion to the PGA TOUR.
On Thursday, Thompson wasn't the only player who flirted with shooting the Nationwide Tour's fourth 59.
Scott Sterling led the tournament for most of the day after posting a 10-under 61 in an early group, only to be passed by Thompson later in the afternoon. He sits alone in second place.
'I haven't played real well here in the past, so this is unexpected,' said Sterling, who chipped in for eagle at No. 9 to make the turn in just 29 shots. 'I've never even made a cut here so a 61 is unexpected -- but I'll definitely take it.'
Thompson's 60 -- the 12th in tour history and third at the Cox Classic -- was a surprise coming from a rookie whose best finish was a tie for 20th place at the Melwood Prince George's County Open in May.
'It just added up to a 60 today,' he said.
Kelly Grunewald shot an 8-under 63 and was alone in third place, while Keoke Cotner and Roland Thatcher were tied for fourth at seven-under 64.
Overall, there were 109 players under par after the first round.
'I'm sure the fans enjoyed it,' said Thompson -- talking about his own round, but surely a statement that could be applied to the entire field. 'It is better cheering for birdies than for players chopping it out of the hay.'
Greg Chalmers, Tom Scherrer, Bob Burns, Jon Mills and Chad Collins shared sixth place at 6-under 65. Nineteen players were another shot further back at 66.