World number two Rory McIlroy got his title defence back on track in the DP World Tour Championship, but admitted he will still need help from elsewhere to claim a fourth victory of the season.

McIlroy has won the European Tour's season-finale twice and never finished worse than 11th in seven appearances at Jumeirah Golf Estates, but struggled to an opening 75 on Thursday, his first over-par score in the event.

That meant a nine-shot deficit to overnight leader Lee Westwood and an early start on Friday alongside Ryder Cup partner Andy Sullivan, the man he edged out in a thrilling final round 12 months ago.

And although a second round of 68 - completed an hour before the final group was due to tee off - got the four-time major winner into red figures at one under par, McIlroy was realistic about his chances.

"If Lee or one of the other guys who played well yesterday don't get to 10 under par I feel I still have a chance," McIlroy said after a round containing six birdies and two bogeys. "I'm hoping for some wind to get up this afternoon.

"Yesterday was just one of those days. I was mentally very flat, still in holiday mode and not quite switched on to what I needed to do. I sort of turned it around today and hopefully can do the same over the weekend."

Playing partner Sullivan fared even better than McIlroy, completing a 66 in style with birdies on the 15th and 16th and an eagle on the last to finish two under par.

Offaly man Shane Lowry added a 71 to his opening day 70 to move to three under par overall.

Lowry was one over for the front nine but bounced back with birdies on 11 and 14 to keep in touch with the leaders.

Race to Dubai leader Henrik Stenson was also among the early starters after a pedestrian 72 on Thursday, the Open champion moving in the right direction with birdies on the third and fourth before dropping a shot on the 12th.

That left Stenson on one under par and alongside his nearest rival Danny Willett, who had birdied the first and third but bogeyed the fifth and seventh.

Stenson has a lead of 299,675 points over Masters champion Willett in the battle to end the season as European number one, although Willett can win the Race to Dubai with victory on Sunday regardless of Stenson's result.

Stenson birdied the 15th and 18th to complete an incident-packed 69, which saw one of his shots hit a female spectator on the head and someone pick his ball up on the second.

"It was a very unfortunate circumstance," Stenson said of the incident with the spectator on the 13th. "I flared my five-iron right and I'm standing there thinking, is it going in the bunker or flying over the bunker, and next thing I see it go into the crowd and hit someone.

"It was actually a mishit up into the wind. It went further than the pin number, so something was quirky there.

"Unfortunately I hit the lady and she went down. But I had some reports later in the round that she was doing okay. I'm just making sure that we're going to get her details so I can send her something nice."

At three under par, Stenson was level with Willett, who had birdied the 14th and 16th, and four behind Ryder Cup team-mates Westwood and Sergio Garcia.

Both men had birdied the par-five second and Garcia also picked up shots on the fourth and sixth.