Lee Westwood made the most of yet another spectacular blowout by Padraig Harrington as he took a two-shot lead at the halfway stage of the $7.5-million Dubai World Championship, the European Tour?s new season-ending championship, here on Friday.

The 36-year-old Englishman drained a 20-footer birdie putt on the final hole for a card of three-under par 69, which gave him a two-day total of nine-under 135 and sole position on top of the leaderboard.

That came after thrice Major champion Harrington had twice hit his ball into the stream on the 18th hole for a double bogey seven.

The Irishman slipped from nine-under to finish tied second at seven-under 137, courtesy of a second-round 69.

Also at 137 was Rory McIlroy, the current Race to Dubai leader, along with overnight leader Robert Allenby (72) of Australia, Colombian Camilo Villegas (71), South African Louis Oosthuizen (66) and England?s Ross McGowan (66).

Westwood and McIlroy are also involved in the battle for supremacy in The Race to Dubai, the re-christened Order of Merit of the European Tour.

McIlroy is ahead by 128,172 euros and whoever wins this week is also ensured the honour of becoming the No1 European player, apart from a 1.5 million bonus.

Westwood started with a couple of birdies and then finished with two on his last three holes for his 69. In between, he dropped a shot on the par-4 eighth.

"Yeah, I?m delighted with 69. It was certainly much harder than yesterday (Thursday) with the wind blowing. If I?m honest, some of the flag positions didn?t really fit my eye, so I was finding it difficult out there. I was playing kind of a plodding game in between the second and 16th holes," said Westwood.

"Some days, that happens. You struggle to get things going, the birdies don?t quite come so freely, and then you have to just dig in there and just grind it out for a while."

Harrington, who famously won the 2007 Open Championship despite going into Carnoustie?s Barry Burn on the final day, has already run up huge numbers when in contention this year.

He lost the WGC-Bridgestone at Firestone to Tiger Woods, and another dunk in the water dashed his hopes of defending the PGA Championship title at Hazeltine. He took 8s in both the tournament, but was better off here as he finished the hole with a double bogey seven.

"It probably has no consequence on whether I?m going to win this tournament or not. I?m glad it wasn?t Sunday afternoon I did it. Much better on a Friday," said Harrington.

"I would have taken a round of 69 going out. I definitely would have taken being one shot out of the lead. But this is a good position going into the weekend."

Despite the double bogey, Harrington was all praise for the 18th hole.

"No, it really is a good hole. It?s a tough hole. You?ve got to hit three good shots up there. As a finishing hole, we normally feel we need a strong par 4, but we?ve got a strong par 5 this week," said Harrington, who was one-over after six holes, but made an eagle and three birdies in his next four.

McIlroy was fast off the blocks, finishing his front nine in 31, five-under par. However, he could not keep up the momentum on the back nine and could only make two bogeys.

"It was like nearly the complete opposite of yesterday. Not best on the front nine and then very good on the back nine, whereas I was the other way around today," said McIlroy.

"I have to think I?m still in a good position going into the weekend to not dwell on the lost opportunities on the back nine there," he added.