Luke Donald and Matteo Manassero will take a two-shot lead into the final round of the PGA Championship at Wentworth on Sunday.
The pair carded very different rounds of 72 to end an absorbing third day tied at five under.
World number one Lee Westwood (69) and Fabrizio Zanotti (69) are poised in second, with Bradley Dredge, Simon Dyson and Raphael Jacquelin two under.
Donald dropped five shots in his first six holes but fought back tenaciously.
With world number three Martin Kaymer at four over and unlikely to finish in the top two, the 33-year-old Donald only needs to finish above Westwood to overtake him in the rankings.
But Donald, who said he felt "invincible" in shooting 64 on Thursday, was soon in trouble as his round threatened to unravel.
He began his downward spiral at the short second when he chipped through the green and then saw the one back roll off the other side en route to a double bogey.
He dropped another shot after catching a bunker at the third, escaped with 'only' a par after finding trees again on the long fourth and amassed a double-bogey after carving it deep into the woods on the sixth.
But the US-based Englishman held his nerve to make four straight pars before clawing his way back with birdies on 11 and 12.
Donald's revival gathered pace with another birdie on 16 to get back to within one of the lead and he drained a long birdie at the 17th to once again tie with Manassero. Despite another drive into the trees on 18, Donald salvaged a par five to book a spot in the last group with the young Italian on Sunday.
"I need to figure out how I can keep it on the short stuff and keep it out of the trees," said Donald. "I felt like Seve [Ballesteros] out there, I was in trees with leaves all over my back. I was dropping balls in high grass and escaping from everywhere and I don't think you can do that two days in a row."
But he added: "I'm very proud, it was a great fight-back. It would have been easy to shoot myself out of the tournament. I certainly didn't feel nervous, I just felt a bit anxious because I didn't quite have the control I'd have liked. I kept persevering and trying things and getting that first birdie was important to right the ship. It wasn't pretty but I'm in with a great chance."
Manassero, already a two-time winner after only turning pro last year, had three bogeys and two birdies on the way out and then came home with nine straight pars.
"I played well. It was probably the most difficult day today," said Manassero, who finished tied 13th in the 2009 Open as a 16-year-old amateur.
"I enjoy courses like this when they play firm and when you don't score so low you can gain shots making pars and saving pars. You have to fight and I think I did it well. It's a special event and it's fantastic to be in this position. It's something you dream of."
Westwood also inched into contention after trailing Donald by eight shots following the first round.
"I'm edging my way in there and this is the kind of golf course where you have to do that," he said. "It's a tough test. It has that feel of a major championship where you have to hang around, trying not to make too many mistakes. I've been out here quite a while now and I know how to get in the right positions."
Asked whether losing the number one spot was a concern, he said: "Not at all. I'm trying to win the PGA Championship."
Donald's playing partner and co second-round leader Quiros also had an adventurous day, amassing a triple-bogey seven on the ninth and a triple-bogey eight on the 17th to record a 76 and slide back to level par.
The lowest round of the day belonged to Rory McIlroy, who birdied 16 and 17 but gambled on reaching the 18th green in two and dropped a shot at the last to finish with a 68 for one over.
Paul Casey and Ernie Els, who on Friday were involved in a spat over the South African's course redesigns, were paired together for the third round and both carded 72 to end two over.
Casey, the 2009 PGA champion, had added to Ian Poulter's criticism and described the new layout - overseen by Els in 2010 and tweaked again for this year - as a "grind".
But asked after his round on Saturday whether the atmosphere with Els had been frosty, the Englishman said he actually agrees with Els' vision.
And Els added: "I feel comfortable with the changes. I'm 98% there. Maybe 15, the front right is a bit too severe. But guys must play now. This is not easy anymore. It's a change of mindset. It's a better course, a better test. The margin of error is like you get at a major."
Both agreed that the course set-up by tournament officials made it too penal in this week's windy conditions, though Westwood said later: "If it's a big tournament, that's how it is. You don't have to birdie every hole and go at every flag. Sometimes par is a good score. I have no problem with hard flags."
Colin Montgomerie went around in level-par 71 to stay two over, Ian Poulter had 73 for two over and Darren Clarke had an eight and a seven in a 74 to end also end two over.
Germany's Kaymer, the defending USPGA champion, slipped back after a one-over 72 took him to four over.