The 29-year-old Austrian took full advantage of the good playing conditions at the Emirates Golf Club to shoot a bogey-free 8-under 64. He made five straight birdies from the 13th hole before finishing with a par.
''I struggled with my putting early on, I didn't even get to the hole,'' Wiesberger said. ''Once I got the pace right on the greens, which was a bit slower than I expected it, then it went nicely.''
''It's a decent score,'' McIlroy said. ''I didn't hit a fairway until the 17th, which was my eighth hole, but I scored well for those holes. I can't complain with 66 to start. You're not going to get the course any easier out there today.''
Uihlein was 8 under through 13 holes, but finished with four pars and a bogey on the 17th.
The dropped shot came after he hit a chip shot short of the green and then failed to get up and down.
''I just got too cute on the 17th. It happens,'' Uihlein said. ''But it was nice to finish with a good par on 18.''