Jinho Choi carded a brilliant round of 64 to set the clubhouse target on top of a congested leaderboard during the final day of the Commercial Bank Qatar Masters.
The South Korean made six birdies and an eagle to catapult himself to 11 under but the top 17 players were separated by just three shots at Doha Golf Club.
Swede Anton Karlsson was alongside Choi having played ten holes, a shot clear of South Africans Christiaan Bezuidenhout, Justin Hardiing and Erik van Rooyen, Belgian Thomas Detry, Spaniard Nacho Elvira, Frenchman Mike Lorenzo-Vera, overnight leader Oliver Wilson and Paraguayan Fabrizio Zanotti.
Choi narrowly missed out on keeping his playing privileges last season after finishing top of the Korean PGA money list in 2017, while Karlsson came through the Qualifying School in 2016 and 2018.
Choi made a big early move, birdieing his first three holes and adding gains on the eighth and ninth to turn in 31 and get to eight under.
Harding started the day a shot back of that mark but birdied the first for the fourth day in a row and then added another at the third to join the group in second.
Detry went five under for the week on the first with a birdie, and with playing partner Karlsson also making a gain from 30 feet, there was a seven way tie in second.
It was not that way for long, however, as Harding birdied the fourth to continue his flying start and take a share of the lead.
Detry then made another gain from eight feet on the second to also share top spot.
Englishman Wilson birdied the first to edge ahead on his own but dropped a shot on the second to slip back into the logjam alongside playing partner Elvira, who had birdied the first after getting up and down from the sand.
Van Rooyen was also in the leading group after three birdies and two bogeys in his opening five holes but they were all soon one back.
Choi had picked up a sixth birdie of the day on the 12th and after just missing the green with his tee shot on the driveable 16th, he holed a huge putt for an eagle and a one shot lead.
Karlsson birdied the seventh after a stunning approach as he moved into the group in second, with Lorenzo-Vera joining him from eight feet on the sixth.
Wilson had saved par after wayward drives on the fourth and fifth but got a flier on his approach to the seventh and a poor chip led to a bogey.
Bezuidenhout replaced him in the group in second, taking advantage of the par five tenth to add to birdies on the fourth and fifth.
Bogeys on the sixth and seventh saw Harding drop off the pace but he made the most of the tenth and then hit a nice approach into the second to get back into double figures.
The group in second was swelling but Karlsson was the man to break out of it with a lovely chip from over the back of the tenth setting up a third birdie of the day.
Zanotti eagled the first but gave a shot back on the second before birdieing the fifth, tenth and 13th to sneak up the leaderboard.
Wilson then became the latest man to birdie the tenth to turn in 36 and join the eight way tie in second.
Jorge Campillo, Maximilian Kieffer and Andy Sullivan were nine under.
