Matt Wallace picked up six shots in 13 holes to move one ahead during day two of the DP World Tour Championship, Dubai.
The Englishman is looking for his fourth win of a remarkable 2018 and he reached ten under with five holes to play in round two of the eighth Rolex Series event of the season.
That left him one ahead of overnight leaders Adrian Otaegui and Jordan Smith and two clear of clubhouse leaders Kiradech Aphibarnrat, Dean Burmester and Tommy Fleetwood.
A win at Jumeirah Golf Estates would see Fleetwood successfully defend his Race to Dubai title if Francesco Molinari finishes worse than fifth tied with one other, and the Italian was five shots off the lead with five holes left in his round.
Rory McIlroy, Patrick Reed and Danny Willett were at eight under coming towards the end of their rounds.
Swedish duo Alexander Björk and Henrik Stenson were in the clubhouse at seven under.
Burmester had turned in 32 with birdies on the third, fourth, fifth and seventh and when he added another on the tenth he joined Smith and Otaegui at six under.
Wallace holed a long putt on the first and took advantage of the par-five second to also hit the front but they were soon all leapfrogged by Björk who carded a 65.
He made birdies on the first, second, sixth and eighth with a bogey on the fourth to turn in 33 and then added further gains on the 12th, 14th and 16th with a dropped shot on the 13th. That had him one off the lead but he holed a monster eagle putt on the par-five last and jumped into the lead.
Smith birdied the second to join the lead, with Wallace putting an approach to four feet on the fifth.
McIlroy and Reed were playing together and putting on a show reminiscent of their singles battle at the 2016 Ryder Cup.
Reed birdied the second but McIlroy was producing the early fireworks, putting his approach to four feet on the first, birdieing the second but then three-putting the third.
He almost aced the sixth and grazed the edge on the seventh and eighth - where Reed made a birdie from 15 feet - before both players hit stunning approaches into the ninth and tenth.
Fleetwood was a picture of consistency and he holed a 30-footer on the first and an 18-footer on the eighth to turn in 34.
Approaches to inside ten feet on the tenth and 11th then had him in a share of the lead, and Burmester made it an eight-way tie with a birdie on the 14th.
A six-footer from Reed on the 11th then brought a fourth birdie in a row and he broke out of the pack.
Wallace made the most of the seventh to join the lead again and Otaegui bounced back from a bogey on the first with gains on the fourth, sixth and seventh to get back into a share.
Another approach to inside ten feet on the 15th got Fleetwood to eight under and Willett recovered from a bogey on the first with four birdies in a row from the sixth.
Burmester got on the last in two and made a birdie to set the target at eight under and make it a six-way tie but Wallace jumped out of the pack with a 25-footer on the 11th.
McIlroy had dropped a shot on the 13th but he made the most of the par-five 14th and then hit a stunner into the 16th to get to eight under.
Smith had dropped a shot on the sixth but he birdied the eighth and left himself a tap-in at the ninth to get within one of Wallace.
Aphibarnrat was a long way back when he turned in 35 but came home in 31 with birdies on the tenth, 12th, 15th, 16th and last.
Willett then dropped a shot on the tenth to drop alongside Björk and Stenson, the two-time champion carding an excellent 66 with eight birdies and two bogeys.
Smith had got himself dialled-in and a second consecutive approach to tap-in range had him back where he had started the day - in a share of the lead.
But he was not there for long as Wallace spun his tee-shot on the par-three 13th back towards the hole to get into double-figures from four feet.
Otaegui then holed an 18-footer on the 11th to get to nine under, while Willett made a birdie on the 12th.
