ABU DHABI (REUTERS, AFP) - Rory McIlroy and Rickie Fowler were among a quintet tied for the lead in a fog-delayed, incomplete third round of the Abu Dhabi Golf Championship on Saturday, as overnight front runner Andy Sullivan's late triple-bogey halted the Englishman's charge.

Poor visibility had again delayed the start of play for nearly three hours, with 60 players waiting to complete their second rounds.

That made for a strange day's golf as the likes of McIlroy, US Masters champion and world No. 1 Jordan Spieth and No. 6 Fowler played nine holes in the morning before returning to the course late in the afternoon.

Spieth battled against a fading sun to complete his third round of the US$2.7 million (S$3.9 million) tournament, playing the final hole of his round in near darkness and as a six-ball with another group.

Spieth, who shot a bogey-free 68 to improve to seven-under overall, was one of only 13 players to complete their weather-disrupted third round.

The 22-year-old American was one behind clubhouse leader, Thailand's Thongchai Jaidee (67), and three shots behind the leaders out on the golf course.

Four-time Major winner McIlroy grazed the pin from nearly 270 yards on the final hole of his second round, eventually making an eagle.

That followed a birdie on No. 17 - his first of the round - to catapult the Northern Irishman level with US amateur champion Bryson DeChambeau on eight under and into the tournament-leading trio alongside Sullivan, 28, who was 10 under.

"I couldn't hole from outside two feet so I thought I'd hit a couple of shots within two feet on the last two holes. It glossed over a pretty average round," said the 26-year-old McIlroy.

Returning to the National course, McIlroy sunk a six-foot birdie on the second hole.

DeChambeau, in contrast, was loose from the tee and fairway and careless in his putting, slipping to seven under on the same green after a wayward four-footer.

Sullivan also struggled with his long game, bogeying the third to slip level with McIlroy on nine under. This duo then birdied four, before Sullivan seized a two-stroke lead with successive birdies at seven and eight.

But on nine, the world No. 37 was left forlornly searching bushes lining the water after an errant drive.

The ball lost, Sullivan's misery deepened as his second tee shot found the rough and the next skidded into a bunker as he made a triple bogey to tumble back to nine under.

McIlroy and American Fowler were both 10 under after nine and 11 holes respectively, sharing the lead with South Africa's Branden Grace (16 holes), England's Ian Poulter (13 holes) and Dutchman Joost Luiten (10 holes).

"The game feels really good and I'm swinging really well," said Fowler, who is four under for the round following scores of 70 and 68 in the opening two.

"I rounded into form as the week has gone on. It's going to be a long day tomorrow."