One of the most popular groupings of the day was the headline trio of World Number One Dustin Johnson, four-time Major victor Rory McIlroy and reigning champion Tommy Fleetwood.
At nine under par McIlroy is just three from the halfway lead in the Middle East, with the rising standard of his play endorsing the theory of him being the man to beat.
Fleetwood, the defending champion and last years European Tour money victor, continued his solid form by hitting all greens in regulation. I feel like I hit the ball very similar.
"I suppose ultimately it means nothing in the grand scheme of things because you can't control what other guys do, but the biggest motivation is that (Martin) Kaymer has won here three times and I've got two".
Fox is one of five players seven shots under the card.
Johnson, 33, is returning to Abu Dhabi Golf Club's National course having finished second to Fleetwood last year and just like in 2017, is in blistering form at the start of the year.
"Dustin shot the most stress-free 64 you'll ever see and Rory just shot the most stress-free 66 you'll ever see".More news: WhatsApp launches new messaging app for small businesses in USA and UK
More news: Nintendo Labo makes the Switch cardboard compatible
More news: Northern California police refuse to cooperate in upcoming ICE raids
The 28-year-old described the eagle as "massive" and he is yet to drop a shot during 36 holes in his first event since October. I didn't really miss many shots, except that sloppy bogey playing the sixth.
"I had close birdie putts over the last four holes and made two of them, so I think that kind of clicked, " said Rahm, set to defend his title next week at Torrey Pines. I hit it really well, had a lot of great looks, but I didn't really hole any putts until I made two nice putts on 17 and 18.
"I felt pretty good out there, and I did everything really well", said the American, who extended his lead at the top of the world rankings in the first week of the New Year with his dominant win at the Sentry Tournament of Champions.
McIlroy, too, was pleased with his first competitive round in 102 days though hinted he wasn't surprised by his good display.
"But who knows? I don't know how they would do it or what they would do or how long it would take them to be able to do it".
"The size of the crowd seemed to get more and more as the day went on".
"I feel like I got what I deserved on the last for staying so patient and it was nice to finish with a three and get myself into contention for the weekend".