Golf – Hong Kong Open:The intriguing battle to be crowned European number one is living up to its billing as Rory McIlroy and Lee Westwood locked horns and couldn't be separated after the first day of the Hong Kong Open where the pair opened with matching 66s in the penultimate event of the season.

McIlroy (€2,352,259) is less than €52,000 behind the Race to Dubai leader Westwood (€2,404,579) in the Race to Dubai standings with only this week’s event in Fanling and the season-ending finale, the Dubai World Championship, to take place next week.

After starting at the 10th the 20-year-old picked up three birdies to turn in 33. His back nine was more of a slow burner as he traded a birdie at the third, his 12th, with bogey at the fifth before a final birdie came at the ninth for a matching nine of 33.

The world number 17 was pleased with his round but said it counts for nothing until the places are decided at the end of the week.

“There are 54 holes left so it doesn’t matter until Sunday,” said McIlroy of his duel with Westwood. “We’re both playing pretty well to be in the positions we’re in so I’m not surprised Lee is up there.”

“I’ve just got to keep doing it. I’m not sure if three more 66s will be good enough so I might need to go a little better over the next three days.”

McIlroy, who lost to Chinese Taipei’s Lin Wen Tang in a play-off 12 months ago, then threw in some tentative mind games by suggesting he holds a slight advantage over Westwood this week because this is his third straight year competing in Hong Kong.

“It’s just a question of getting used to the grain,” he said in reference to the greens. “I don’t struggle too much. You just have to look to see which way the grass is going and then guess how much the grass is going to affect a putt. There’s no exact science to it.”

Westwood's final birdie of the day came at the 18th, his ninth, as the 36-year-old traded six birdies in all with two dropped shots and is pleased with his game.

“It was good,” said the world number four. “The only green I missed was the last hole I played (ninth) and that is a tough hole. I wouldn’t say I flushed it but I had enough control to hit 17 out of 18 greens.

“I had a lot of chances but found the greens very puzzling. I think I’m at a real disadvantage having only played the course once before (in the pro-am).

“It’s alright learning a course tee to green – it’s pretty obvious how you play tee to green – but on the greens, it’s such an advantage having played a few tournaments round here. So to start with four-under 66, I’m delighted.

“The only two bogeys I made were three putts and I had a load of chances.”

“The grain, it really does affect the ball, as much as anywhere. Sometimes it breaks up the hill.

“After about six or seven holes I called my caddie in and he had more of an idea. We gradually got it right and I eventually holed a couple,” added Westwood, apparently conceding some advantage to McIlroy.

As for the Race to Dubai, Westwood said he was trying not to think about it while competing this week. “I’m trying to win the UBS Hong Kong Open and that’s all,” he insisted.

If McIlroy is to overcome Westwood at the top of the European standings - in only his second full season on tour - he will have his work cut out against a player who already knows what it takes to become Europe's number one.

This year's Portugal Masters winner topped the European Order of Merit in 2000 and has finished inside the top 10 on no less than eight other occasions.

This week's winner will receive a cheque for €279,288 compared to the runner-up cheque for €186,190 with third earning €104,902.

Outside the top three the money starts to drop off as sixth place will win €58,651 and seventh €50,272.

At this stage of the season it's all a number's game but suffice to say if McIlroy wins he will go top of the standings even if Westwood finishes second.

At four-under the pair are four shots off the first round lead held by little-known Udorn Duangdecha from Thailand, who fired an eight-under par 62 that contained no less than 10 birdies and two dropped shots.

For much of the day Robert-Jan Derksen from The Netherlands held the lead after his 63 but by day’s end he had to settle for second place.

Peter Lawrie (66) joins McIlroy and Westwood on four-under, while Graeme McDowell opened with a 67.

Darren Clarke dipped below par with his one-under 69, but Shane Lowry (72) and Michael Hoey (73) finished the opening day two-and three-over respectively.