World no. 5 DeChambeau had two straight bogeys on the seventh and eighth holes but ended the round strongly with four birdies after the turn, for a total of six on the day, to go 16-under for the tournament.
DeChambeau, however, was a massive seven shot victor of the event, justifying his favouritism for the event and that he was the leading world ranked player in the field ahead of the event.
Li Haotong, who is looking to claim back-to-back victories at the Emirates Golf Club, is the nearest challenger to DeChambeau after moving into second place outright with a third straight 67 of the week.
"I had a couple chances to right the ship and be three or four ahead, but I'm only one ahead. I can't express to you the words how awesome it would be to win on the European Tour".
The South African veteran was bogey-free and made just two birdies - on the third and 18th holes - to sit tied third alongside England's Matt Wallace. "I've got a lot of work to do tomorrow".
"I'm still leading.it's fantastic. but my expectation levels are for how I know I can perform, and I feel like I'm under-performing a little bit". The old record for lowest tournament aggregate was set previous year by Li Haotong (23-under par).
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"Especially under the gun with the heat of some good players coming up and playing well from behind me, I knew I needed to step on the pedal and that's what I did today", DeChambeau said.
Herbert was informed of the ruling on the ninth hole and even though he showed remarkable tenacity and birdied his next four holes, he fell back for a tie of fifth place at 12-under.
"I did play really solid compared to the last two rounds and my long game being much better".
"I know even with not my best, I can get it done", DeChambeau said.
"Whether it's air pressure, firmness values, miles per hour on the ball speed, spin rates...we're trying to figure out as much as possible so I can be as consistent as possible and obviously it's showing".