Lee Westwood produced the perfect response to his World Cup disappointment as defending champion Rory McIlroy carded his worst ever round in the DP World Tour Championship.

McIlroy has won the European Tour's season-finale twice and never finished worse than 11th in seven appearances at Jumeirah Golf Estates, with a 72 in 2010 his worst score in 28 rounds.

However, the world No 2 could only manage an opening 75 to lie joint 55th in the 60-man field, nine shots behind Ryder Cup team-mate Westwood.

It took McIlroy 14 holes to register his first birdie of the day and although he swiftly added another on the next, the four-time major winner double-bogeyed the 16th after needing two attempts - the second minus his right shoe and sock - to play from the edge of a water hazard.

In contrast, Westwood carded seven birdies and just one bogey to match his opening 66 in the inaugural event in 2009, which he went on to win by six shots to become European No 1 for the second time.

"That's certainly in the top two or three performances in my career," Westwood said. "Maybe even the best performance of my career, knowing that I needed to win to beat Rory in the Race to Dubai, and did that by six and pretty much dominated the field over the weekend.”

Westwood had been due to make his World Cup debut in Melbourne next week, but with Danny Willett pulling out to protect a back injury, Ryder Cup team-mate Chris Wood took his place as the next highest English player in the world rankings at the end of July.

Under tournament rules, Wood was also able to select his partner and opted for Andy Sullivan, much to Westwood's disappointment.

"I've been looking forward to it for a few months now, so it's frustrating," said the 43-year-old, whose frustration was probably heightened by seeing Wood and Sullivan shoot 75 and 76 respectively.

"I'm disappointed not to be playing. I can understand him picking a mate and he's picked a very good player. It's probably more to do with the rules than anything.

Westwood's former Ryder Cup partner Nicolas Colsaerts and France's Julien Quesne shared second place on five-under, with Sergio Garcia, Francesco Molinari and Joost Luiten a shot further back.

Race to Dubai leader Henrik Stenson managed just one birdie in an opening 72, with Danny Willett, second on the money list, and Alex Noren both one shot better off.