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.
Watch the final round of the Omega Dubai Desert Classic live on Sunday from 8.30am on Sky Sports Golf and Sky Sports Main Event.
He is now one shot clear of defending champion, China's Li Haotong, with England's Matt Wallace and four-time major victor Ernie Els three shots off the pace in a tie for third.
"Man, I'm just not 100 percent with my golf game right now", DeChambeau said after his 4-under 68 in the third round, which gave him a one-shot lead over defending champion Li Haotong of China. "Shoot, I'm still leading, obviously, it's fantastic". But my expectation levels are for how I know I can perform, and I feel like I'm underperforming a little bit.
"It's a lot of hard work with my caddie, just really grinding and trying to figure out how to take account of all the variables out there", DeChambeau said of his approach to the game.
The 25-year-old DeChambeau was one-over par for his round after a bogey on the eighth hole, but made a long birdie putt on the ninth to make the turn at even par, and then added four more birdies on the back nine.
Spain's Alvaro Quiros is also 11-under, with American Bryson DeChambeau and Australia's Lucas Herbert on 12 under.
"But again, going back to it being my first worldwide win, I really couldn't be more pleased to have this tournament be my first global win, European Tour win". That was one of the things I talked about this week, was reading the green right, and we've done a pretty darned good job so far.
DeChambeau started his third round with five straight pars, and was three shots behind after bogeys at Nos.
"It definitely would mean a lot, and I just want to play my best over there and hopefully hold the trophy again", Li said, after signing for a third-consecutive round of 67.
"I know even while not at my best, I can get it done", DeChambeau said.