Oliver Fisher picked up ten shots in his first 12 holes on day two of the Portugal Masters to share the lead and threaten the first 59 in European Tour history.
The Englishman began the day eight shots behind overnight leader Lucas Herbert but his incredible run of scoring moved him to ten under alongside the Australian and local favourite Ricardo Gouveia.
This event has seen others come close to a 59 in recent seasons, with Scott Jamieson in 2013 and Nicolas Colsaerts in 2014 both having putts on the their last hole to get to the magic number.
After turning in 28 to match Suttijet Kooratanapisan's lowest nine of the season from the AfrAsia Bank Mauritius Open, Fisher birdied the tenth, 11th and 12th to maintain his momentum.
Gouveia picked up six shots in his first 13 holes, while Herbert turned in 33.
Major Champion Charl Schwartzel, 2012 winner Shane Lowry, Frenchman Raphaël Jacquelin and Swede Marcus Kinhult were eight under.
Schwartzel made the big early move, birdieing the 11th, 12th, 14th, 15th and 17th to turn in 31 and get within one of the lead.
Another birdie on the first put him in a share but he was soon leapfroged by Jacquelin who birdied the tenth and 12th and then added an eagle at the par four 15th to get into the lead.
Herbert had started with four pars but he eagled the fifth to become the first man into double figures and reclaim top spot.
A bogey on the 17th stalled Jacquelin's charge and he was replaced at nine under by Gouveia, who made four birdies in a row from the 17th after going birdie-bogey-birdie from the 13th.
That move was nothing compared to Fisher, however, who started with three birdies and then eagled the fifth and made a gain on the sixth to be six under through six.
Another birdie on the eighth meant he had matched the low nine of the season and when he picked up an eighth shot of the day on the tenth, talk of a 59 was swirling round Vilamoura.
Gouveia made it five birdies in a row from 12 feet on the third to share the lead but Fisher also made another gain as his remarkable run continued.
Fisher got on the par five tenth in two and while he missed his eagle effort, he had an eighth birdie of the day and a share of the lead.
Kinhult made birdies on the tenth, 12th, 14th, 15th and 18th as he turned in 31, while Lowry birdied the first after starting with nine pars.
Nicolas Colsaerts and Stephen Gallacher were four under for the day to sit at seven under, a shot clear of Jorge Campillo, Ashley Chesters and Thorbjørn Olesen.
