Lucas Herbert moved into an outright lead on moving day at the Portugal Masters, while Tom Lewis surged into contention with a brilliant 61.
Seeking his first European Tour title and a full tour card for next year, Herbert's 64 means he holds a two-shot lead over Lewis, with Eddie Pepperell and Marcus Kinhult four behind the leader in a tie for third.
After his record-breaking 59 on Friday, overnight co-leader Oliver Fisher signed for a 69 in Vilamoura on Saturday, meaning he sits five shots off the pace along with Renato Paratore and Mikko Korhonen.
Leader Herbert carded eight birdies and dropped only one shot on the 16th as he continued a fine week to reach the final day in a strong position. He sits at 19 under par after his best 54-hole score on the tour, bettering his previous record through three rounds by seven shots.
"I think this week is as close to the A-game as we get," Herbert told the European Tour's website. "Some good confidence going into tomorrow and hopefully that form sticks around. In the position
"I just need to get out of my own way. I've played really good up until this point. I don't really need to do anything different or special."
Englishman Lewis hit 10 birdies in superb a bogey-free round – his lowest on the tour - to provide the main challenge to Herbert. After shooting 72 on day one, rounds of 63 and 61 have put him firmly in with a chance of winning a tournament he claimed back in 2011, his only European Tour success.
Pepperell, who was overlooked by Europe for the Ryder Cup, had shared the lead with Herbert and Fisher overnight and started brightly with three birdies in the first five holes at Dom Pedro Victoria Golf Course, but ran out steam and eventually had to settle for a 68
That means he is joined by Kinhult at 15 under, the Swede's round of 65 including an eagle at the second.
A 68 for Sergio Garcia, who is using the event as a tune-up for the Ryder Cup, means the Spaniard sits in a tie for 27th.
