Updated

Shanghai, China (SportsNetwork.com) - Rory McIlroy fired a 7-under 65 on Thursday to grab a 2-stroke lead after the opening round of the WGC - HSBC Champions.

The 65 was McIlroy's lowest round since he carded a 64 in the third round of the Deutsche Bank Championship, the second event of the FedExCup playoffs. It was McIlroy's third 65 of the year.

Gonzalo Fernandez-Castano, who won last week's European Tour event, and Jamie Donaldson both carded 5-under 67s and share second place at Sheshan International Golf Club.

Reigning U.S. Open champion Justin Rose opened with a 4-under 68. He was joined in fourth place by Jordan Spieth, Tommy Fleetwood and Bubba Watson.

Ernie Els, Dustin Johnson and Graeme McDowell are among seven players tied in eighth at minus-3.

Two-time champion Phil Mickelson was within one stroke of the lead as he had six birdies through 16 holes. On the par-5 eighth, his 17th, Mickelson dumped two balls in the water en route to a quadruple bogey. He dropped another stroke on the ninth as he posted a 1-under 71 in the first round. That left him tied for 28th.

McIlroy, who had broken par in just 10 of his last 24 rounds, traded a birdie for a bogey from the 10th. He bounced right back with a birdie on the 12th.

The two-time major champion added birdies at 14, 16 and 18 to head to the front nine at minus-4. Following his birdie at the 18th, McIlroy also birdied the first and second to make it three in a row.

McIlroy was in the lead at that point and remained there as he parred five in a row from the third. At the par-5 eighth, McIlroy's third stopped seven feet from the hole and he drained that putt for his final birdie. He parred the ninth, his last, to grab the first-round lead.

"It's a great start. It's only one round of golf, but it's definitely the way I wanted and needed to start this week, keeping in mind that I obviously want to play myself into Dubai and try to pick up my first win of the season, as well," McIlroy stated.

"It felt pretty good out there. I let a couple of putts get away from me, a couple of the downhill ones, but I was able to hole ones coming back, which was good. I've tried to stay patient the entire season, and I know that if I believe that I'm working on the right things and I am working on the right things, then things will start to fall into place sooner or later."

Fernandez-Castano also started on the back nine Thursday, and like McIlroy, he birdied the opening hole. The Spaniard then ran off five consecutive pars from the 11th.

He faltered to a bogey on No. 16, but came back with a birdie on the 18th to make the turn at minus-1.

After four straight pars to start the front nine, Fernandez-Castano poured in four consecutive birdies from the fifth to jump to minus-5. He parred the last to end there.

Donaldson dropped in back-to-back birdies from third to quickly get into red figures. After four pars in a row, he wrapped bogeys at nine and 11 around a birdie on the 10th.

The Welshman converted a birdie try at 13 and made it two in a row as he also birdied the 14th. He made eagle on the driveable par-4 16th, then traded a bogey for a birdie over the final two holes.

NOTESL McIlroy has yet to win a World Golf Championship event ... Defending champion Ian Poulter mixed four bogeys, three birdies and an eagle in a round of 1-under 71.