Afternoon starters traditionally tend to struggle to post low scores in the Middle East as the wind picks up and the greens dry out and get firmer, but Sterne and Kurt Kitayama put those thoughts to one side to climb above early leaders Sergio Garcia and Justin Harding.
The pair looked set to share the clubhouse lead at the end of the first round but South African Sterne rolled in his ninth birdie of the day at the ninth - his last - to nudge one ahead of the American at eight under par.
Sterne, who has won six European Tour events, is playing in only his fifth event since undergoing wrist surgery last March.
"Yeah, pretty happy," Sterne said. "When I was in trouble, I got out of it and made some good par putts and kept the round going and I hit a lot golf shots as well. Made quite a few birdies.
"So today, I was pretty happy with the performance."
Kitayama - starting on the back nine - made a fast start with a hat-trick of birdies from the 11th before dropping his only shot of the day at the 14th.
The American hit back with an eagle two at the 17th before reaching the turn with another birdie to sit one adrift of clubhouse leaders Garcia and Harding.
Two groups back, Sterne was making his move after also reaching five under through nine holes following gains at the tenth, 11th, 13th, 15th - where he was inches from a hole-in-one - and 17th.
Kitayama and Sterne simultaneously became co-leaders when they birdied the third and first holes respectively. The latter nudged ahead on his own with another gain at the third but the American rolled a testing 20 footer to join him at seven under.
The South African climbed to eight under thanks to an 15 foot birdie putt at the fifth, only to hand the shot back immediately at the next.
Kitayama will be disappointed not to profit on birdie opportunities as putts slid by the cup at the eighth and ninth, while Sterne managed to salvage pars at seventh and eighth before holing the decisive putt at the last to take the lead on his own.
"I haven't played this well in a while, so it's nice to get a round like this," Kitayama said.
Garcia produced another vintage display as he rekindled old memories in Dubai.
The World Number 45 won this event in 2017 before going on to claim his maiden Major Championship at the Masters Tournament later that year.
He carded a flawless 66 - the 11th time he has recorded a round of 67 or better at Emirates Golf Club - to get to six under par.
Harding quietly plotted his way up the leaderboard after bouncing back from an opening bogey with an eagle and five gains - including three in his last four holes - to take the early lead before he was joined by Garcia.
Casey was making his first appearance at this event since 2014 but did not need any time to adjust to the 12 hour flight time from the United States.
The Englishman produced some magnificent iron play as he birdied five of his first seven holes en route to five under par.
Otaegui briefly held co-leadership alongside fellow Spaniard Garcia and Harding but carded his only bogey of the round on his penultimate hole after six birdies.
Detry rolled in a spotless 67, while MacIntyre finished birdie-birdie to reach five under.
Thai Kiradech Aphibarnrat, Spain's Adri Arnaus, Tommy Fleetwood, Frenchman Romain Langasque and Finn Kalle Samooja were joined at four under by Ross Fisher, two time Major Champion Martin Kaymer and Australian Wade Ormsby.
Nacho Elvira was rewarded with a four night ultra all inclusive stay at JA Resorts and Hotels after the Spaniard aced the 170 yard par three 11th on Thursday afternoon.