Lucas Herbert recorded his best-ever 54-hole score on the European Tour to take a two-shot lead into the final round of the Portugal Masters.
The Australian carded a 64 to get to 19 under at Dom Pedro Victoria Golf Course and lead the way from England's Tom Lewis, who signed for his lowest ever European Tour round with a stunning 61.
The total was Herbert's best after three rounds by seven shots and his best outside of his homeland by 12 as he aims to become the first wire-to-wire winner since Matt Wallace at last season's Open de Portugal at Morgado Golf Resort
The 22 year old is playing off invites this season but has a great chance to earn his playing privileges, sitting 103rd in the Race to Dubai Rankings presented by Rolex after four top tens.
“I think this week is as close to the A-game as we get,” he said. “Some good confidence going into tomorrow and hopefully that form sticks around. In the position I want to be in so not much more we can do.
“I just need to get out of my own way tomorrow, to be honest. I've played really good up until this point. I don't really need to do anything different or special, just stick to the processes, keep picking the right shots and doing a good job with all of that. That's all I can control.”
Lewis bogeyed the 16th and 18th to sit one over after 18 holes but has made 18 birdies with no dropped shots since, carding rounds of 63 and 61 as he looks for a second win in this event.
His victory in 2011 came in just his fifth start on Tour and he has a win and a tie for third in the last two weeks on the Challenge Tour.
Swede Marcus Kinhult and England's Eddie Pepperell were at 15 under, a shot clear of Finn Mikko Korhonen, Italian Renato Paratore and England's Oliver Fisher - who followed up his history-making 59 on Friday with a 69.
Kinhult got off to a flying start, making a birdie on the first and an eagle on the par four second to jump into a share of top spot but Herbert made a long putt for an opening gain to edge into the solo lead.
Pepperell made a birdie of his own from five feet on the second but Kinhult holed from similar range at the fifth to hit the front on his own.
A brilliant Pepperell approach to the fourth had him back in a share before Kinhult hit an even better one into the seventh for a birdie.
The duo were going toe-to-toe and Pepperell got on the par five fifth in two for another gain to join Kinhult, with Herbert also taking advantage to sit one off the lead.
Lewis made four birdies in a row from the second and another birdie at the seventh saw him turn in 30 before a long putt on the tenth and a brilliant approach into the 11th meant he was just one back.
A long right-to-lefter on the seventh moved Herbert into a share of the lead and he replaced Pepperell who failed to get up and down on the same hole. The 27 year old hit back from 40 feet on the next but Herbert followed him in to strike out on his own again.
His lead was up to two when he holed a long left-to-righter on the ninth and ahead on the par five 12th, Lewis got on in two to make a third birdie in a row and share second.
An approach to four feet at the 11th extended the lead to three but Lewis set about reeling Herbert in, holing from ten feet at the 15th and making the most of the par five 17th.
Herbert then holed from four feet on the 15th to go two ahead, with Kinhult and Pepperell both making gains on the same hole after dropping shots on the 11th and 12th respectively.
A three-putt on the the 16th then brought the first Herbert bogey of the week and the lead was back down to one but he restored his cushion after getting on the 17th green in two.
Korhonen made eight birdies and a single bogey in a 64, while Paratore also had one blemish in his 67.
Fisher bogeyed the third to turn in 36 as he struggled to find his feet after Friday's 12 under par effort but he made gains on the tenth, 12th and 14th.
Spaniard Pep Angles and China's Li Haotong were at 13 under, one ahead of French pair Raphaël Jacquelin and Adrien Saddier, 2012 champion Shane Lowry, 2015 winner Andy Sullivan and Australian Jason Scrivener.
