DUBAI, January 30, 2014 (AFP) - Firing seven birdies and an eagle, the 24-year-old from Northern Ireland continued his storming start to the season which saw him take second place at Abu Dhabi two weeks ago, his first tournament since winning the Australian Open in early December.
It was a flawless display of golf that left playing partner Tiger Woods in the shade, although the world number one was happy to settle for a four-under 68 in what is also his second tournament of the year.
His opener last week at Torrey Pines, San Diego ended in him firing a 79 on Saturday to miss the secondary cut at the Farmers Insurance Open.
The third member of the group, defending champion Stephen Gallacher of Scotland, was also high up the early leaderboard with a 66.
McIlroy said that the round and score was one of his finest for a while.
"Definitely up there. Controlled my irons a little better (than at Abu Dhabi), distance control was better. Wedges are still not where I want them to be but it's getting close. It was good."
With playing conditions ideal at the par-72 Majlis Course, hosting the 25th anniversary of a tournament which blazed new paths for the European Tour and put the Gulf region onto the golfing map, scoring was understandably low.
Playing down the easier back nine to start with, McIlroy, on the rebound after a frustrating 2013, had five birdies in seven holes from the 12th to briefly take the lead at the turn.
Minutes later Frenchman Julien Quesne pitched a sand wedge into the 17th green from 105 yards and it spun back into the hole for eagle which eased him out to six under.
But a birdie at the second and a 10-foot putt for eagle at the third saw McIlroy back on the pace. He then sunk a 15-footer at the par-three seventh to get to nine under and only Quesne was within three strokes of his pace-setting at that stage.
The Ulsterman parred his way in from there, coming up just short with a 15-footer for birdie at the last. It was his first 63 in tournament play since the first round of the Hong Kong Open in 2010
Woods, meanwhile, started well with four birdies down the back nine and while he struggled for accuracy off the tee on the way in, his short game was good enough to avoid any bogeys.
"Overall it was a pretty good score. Maybe could have gotten two more out of it," said Woods. "I hit a lot of good putts which was nice. Last week I didn't do it. It was nice to actually play well again."
Quesne was rock solid till the ninth, his last, when he went into the water and took a double bogey to card a fine 66.
Late in the day Italian Ryder Cup player Edoardo Molinari came in with a 65 to be solo in second place two shots behind McIlroy.
A shot further back level with Quesne and Gallacher were South African Richard Sterne, Ireland's Damien McGrane and Matthew Baldwin of England.
Englishman Robert Rock was on 67 tied with Soren Hansen of Denmark.
Among the later starters, world number three Henrik Stenson had a rollercoaster of a round.
The big Swede, the outstanding player in the world over the last few months, struggled early on with three bogeys in his first five holes, but he battled his way back with four straight birdies from the eighth and remained in contention with a 70.
Playing partner and record three-time winner in Dubai Ernie Els also started poorly, but unlike Stenson he was unable to claw his way back as he came in with a disappointing 74.
Els was back using a shortened putter ahead of the ban on anchored putters from the start of 2016.
Leading scores on Thursday in the first round of the $2.5 million Dubai Desert Classic, part of the European PGA Tour:-
Majlis Course, par-72
63 - Rory McIlroy (NIR)
65 - Edoardo Molinari (ITA)
66 - Stephen Gallacher (SCO), Julien Quesne (FRA), Richard Sterne (RSA), Damien McGrane (IRL), Matthew Baldwin (ENG)
67 - Robert Rock (ENG), Soren Hansen (DEN)
68 - Tiger Woods (USA), Paul Lawrie (SCO), Soren Kjledsen (DEN), Ottie Hennie (RSA), Romain Wattel (FRA), Jorge Campillo (ESP), Thongchai Jaidee (THA),
69 - Brooks Koepka (USA), Roope Kakko (FIN), Alvaro Quiros (ESP), Mikko Ilonen (FIN), David Horsey (ENG), Jamie Donaldson (WAL), Tommy Fleetwood (ENG), Darren Fichardt (RSA), Magnus Carlsson (SWE), Simon Dyson (ENG), Noh Seung-Yul (KOR), Marco Crespi (ITA), Justin Walters (RSA), Francesco Molinari (ITA), Brett Rumford (AUS), Raphael Jacquelin (FRA), Alexander Levi (FRA), Scott Hend (AUS)