Rory McIlroy and Thomas Bjorn, both former winners of the title, share the lead at the halfway stage of the Omega Dubai Desert Classic.

World number two McIlroy, whose first professional title came on the course three years ago, set the clubhouse target at 13 under par by adding a 65 to his opening 66. But 40-year-old Bjorn, who beat Tiger Woods head to head to lift the trophy in 2001 and did it with a tournament record score, then matched the Ulsterman's round and total.

Overnight pace-setter Rafael Cabrera-Bello is one back after a 69, while only two behind are world number four Martin Kaymer, whose 67 included his first-ever hole in one at the 186-yard seventh, Scotland's Scott Jamieson and Frenchman Gregory Bourdy.

World number three Lee Westwood is part of the chasing pack, three closing birdies giving him a 65 and 10 under aggregate. McIlroy turned in a four-under 33, but for the second day running missed an eagle chance of under 10 feet at the long 18th and then failed from five feet on the first.

Kaymer, out in 34, drew level with a birdie on the second, but by the time he came to the seventh he was three behind. While he three-putted the short fourth McIlroy birdied the long third, sixth and eighth.

The 22-year-old US Open champion told Sky Sports: "I just kept picking up birdies along the way and it puts me in a great position.

"I feel a lot more confident than I did in Abu Dhabi ."

He lost by one to Robert Rock there two weeks ago after incurring a two-shot penalty for brushing sand away from his line off the green.

Westwood shares seventh place with Kaymer's fellow German Marcel Siem and Scot Stephen Gallacher, who shot 65 a day after holing in one at the 15th.

American John Daly had an eventful time. A six on the long 10th and quadruple-bogey eight at the 12th put the former Open champion in severe danger of missing the cut, but he fought his way back to one under and had to wait to see if he had made it through.