England’s Oliver Fisher was the 20th player in Tour history to putt for a 59 but the first to achieve the feat after his birdie effort to shoot 58 lipped out.
The 12-under round on the par-71 Dom Pedro Victoria Golf Course vaulted him to the top of the Portugal Masters leaderboard where he shares honours with Lucas Herbert and fellow Englishman Eddie Pepperell.
Fisher was out in 28 and home in 31, 12 shots better than his opening even par effort and leapfrogging 92 players in the process.
“It's a great feeling,” he said. “It feels great to make history here in Portugal. It's a great tournament and it's great for the European Tour and obviously myself to shoot 59.
We’ve had over 690,000 rounds on the European Tour...September 21, 2018
“I was chuffed with the day. When I went out I was at level par and trying to make the cut, and then shooting that, it was just a great day all round.
“It was fun, I tried to enjoy it and thankfully I got over the line.”
He said he began to think the historic feat was possible when he got to 10 under through 12 holes.
“I started the round really well with three birdies and then managed to hole a bunker shot on the fifth, so I was five under through five,” he said.
“I missed a couple of chances on seven and nine, so I could have quite easily been out in nine under.
“I got on to a run around ten, 11, 12, so then I was thinking 59 was on the cards with 15 and 17 ahead of me.
“The big hole for me was 16. I hit a poor shot into the green and had a tough decision to make whether I chipped it or putted it. Went with the putter and left it a long way short and managed to hole a 20-footer for par.
“After that it was about hitting a couple of good drives on 17 and 18 which I did, and I just tried to enjoy it really.”
While Fisher was basking in the glory of making history Australia’s Herbert went about his business with little fanfare but that didn’t make his 4-under 67 any less impressive.
The 22-year-old backed up a stunning opening 63 with a second consecutive bogey free scorecard, an eagle and two birdies ensuring he maintained a share of the lead in a low scoring event.
Herbert is on the verge of securing status on the European Tour courtesy of his position in the Race to Dubai rankings but knows a victory would eliminate all doubt.
“I would have liked to have probably taken a bit more advantage of those conditions but I'm still happy to be in the position that I am going into the weekend,” he said after his round.
“The one thing lacking from the résumé at the moment is a win so if I can keep putting myself in a good position going into Sunday that would mean quite a lot - to get a win out here in Europe.”
Herbert is one of five Australasians to qualify for the weekend, Jason Scrivener also playing nicely to be in a share of eighth with two rounds remaining.
The West Australian sits 11thon the Race to Dubai standings and in danger of losing his status but a good finish this week could secure his card for next season.
New Zealanders Josh Geary (T25) and Ryan Fox (T52) joined Jason Norris as the only others to make the cut.
Sam Brazel Richard Green, Jack Munro and Nick Cullen all have the weekend off.
RULES - REPAIRING DAMAGE TO THE GREEN:
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