(CNN) -- Lee Westwood stole an early march on European Tour money list leader Rory McIlroy as he fired a superb six-under-par 66 on the opening day of the season-ending Dubai World Championship.
The Englishman, second to McIlroy in the inaugural Race To Dubai standings, ended Thursday's first round tied for second -- two shots ahead of the young Northern Irishman.
McIlroy was in a group of five players tied for fifth, three shots behind leader Robert Allenby of Australia, who cannot claim the order of merit prize even if he wins the $1.25 million tournament.
If those positions were to stay the same, world No. 5 Westwood will be crowned champion on Sunday. The two leading players were drawn to play together for the first round, but will have different partners on Friday -- Westwood tees off with Colombia's Camilo Villegas and McIlroy with Sweden's Johan Edfors.
"It will be nice not to play with him tomorrow, just to concentrate fully on my own score and on my own game," McIlroy told reporters.
"I think it will be good for both of us not to play together. We're both just trying to win the Dubai World Championship and whatever happens after that, then so be it."
Germany's Martin Kaymer, who is third in the standings, was tied for 22nd after carding 71 while fourth-placed Englishman Ross Fisher -- the only other player with a chance of taking the title -- was equal 40th after a one-over 73 following a double-bogey at his first hole.
The 20-year-old McIlroy will take the title no matter where he finishes if Westwood places outside the top seven, Kaymer the top four and Fisher the top two.
But it was Allenby who set the early pace at the Jumeirah Golf Estates' Earth Course as he started an ended his round of 65 with a birdie.
The 38-year-old, who returned to full membership in Europe in 2009 after spending the past 11 years on the U.S. PGA Tour, suffered only one blot on his card as he bogeyed the par-five 14th hole.
Westwood, who won the money list in 2000 after overhauling Darren Clarke in the final week, also dropped a shot at 14 but then birdied three holes in a row.
He shared second place with compatriot Chris Wood, making his return after an ankle injury a month ago, and Villegas.
"There's a long way to go and a lot of water to go under the bridge before we get to Sunday," Westwood said.
"You're going to have to play well to get into contention on Sunday, so to be bothered about anything on the first tee on a Thursday other than trying to hit it down the middle and get on the green in two to give yourself a birdie chance is irrelevant as far as I'm concerned.
"I looked at the leaderboard and saw Robert Allenby at seven under. What Rory is doing didn't really have any effect on the way I was thinking."
The 21-year-old Wood, third at the British Open in July, covered the closing four-hole stretch -- which has been dubbed "the Golden Mile" -- with four successive birdies despite suffering pain in his tired ankle.
"That's the first time I've played 18 holes since the injury. I was on crutches for two and a half weeks but it's recovered well," he said.
McIlroy, whose only dropped shot was at the par-four eighth hole, was tied with three-time major winner Padraig Harrington, Australia's former world No. 3 Adam Scott, South Africa's Thomas Aiken and Wen Chong Liang of China.