American Cameron Young shot an eight-under 64 to pull three strokes clear at the halfway stage of the Dubai Desert Classic with defending champion Rory McIlroy well off the pace.

Young, made nine birdies and a solitary bogey as he added to his opening 67 to reach 13 under par overall.

England’s Andy Sullivan and Poland’s Adrian Meronk are his nearest challengers at 10 under.

McIlroy, a three-time winner of the event, is 10 shots adrift of Young.

The Northern Irishman recorded five birdies in his second round but was left to rue dropped shots at the the eighth, ninth and eleventh holes.

Meanwhile, world number 25, Young, who is chasing a first victory on both the PGA Tour and DP World Tour, said: “I putted fantastic. I made a couple of long ones yesterday and then made a few more today that had no right going in.

“I hit a bunch of good putts, but just one of those days where you kind of have a couple of 30-footers and you look up and they are going right in the middle, which doesn’t happen all that often to have a bunch of them in one round.

“I’m doing a really good job of staying out of my own way. I realised it was going well early, but the back nine, at the same time, it feels like you should do that to some extent, especially in the morning with not much wind.”

Meronk, who won three times on the DP World Tour last year and was voted player of the year by his peers, registered three birdies on the front and three on back nine as he carded a six-under 66, while Sullivan’s returned a second successive 67.

Dubai Invitational winner Tommy Fleetwood celebrated his 33rd birthday with a 70 to finish at five under overall, three shots ahead of his compatriot Tyrell Hatton and Europe’s Ryder Cup captain Luke Donald.