DUBAI (Reuters) - Rory McIlroy struggled to a 75 and the other contenders to top the European money-list also made slow starts in the season-ending DP World Tour Championship first round in Dubai on Thursday.

Experienced Briton Lee Westwood led the field with an opening 66 but British Open champion Henrik Stenson, who leads the money-list, shot level-par 72 and his Swedish compatriot Alex Noren and Britain's U.S. Masters winner Danny Willett had rounds of 71.

World number two McIlroy, fourth on the money list, needs victory in Dubai to win the race with Stenson finishing outside the top 45, Willett failing to make the first five and Noren the top two.

But the Northern Irishman had problems on the greens and made a double bogey and four bogeys to slump to a tie for 55th place in the 60-man field.

Frenchman Julien Quesne and Belgian Nicolas Colsaerts were tied for second behind Westwood after rounds of 67, one shot ahead of Spain's Sergio Garcia, Italian Francesco Molinari and Dutchman Joost Luiten.

"This is as good as I've played for quite some time," Westwood told reporters. "I've found a couple of keys in different parts of my game and I've been working hard on them.

"Didn't seem that easy out there. Some days you feel like there's a lot of birdies out there but today I think was a pretty stiff test and I think you can't have any flaws in your game if you want to shoot a good score."

Swede Stenson described his own performance in Dubai as "average".

"It wasn't my best day," he said. "I'd say the good putts I hit didn't go in and the bad ones certainly didn't.

"Not much happening out there, one bogey, one birdie. I think it's been a while since I played a round with only one birdie."

(Reporting by Ed Osmond, editing by Pritha Sarkar)