Graeme McDowell has set his sights on securing his Masters invitation before Christmas after a six-under 66 gave him a share the lead with US PGA champion Y.E. Yang going into the final round of the US$5.75 million Chevron World Challenge in California.

The pair lead by a shot on 10 under par from Padraig Harrington and Lee Westwood and world No 55 McDowell knows he has a golden opportunity to take full advantage of his late invitation to replace the beleaguered host Tiger Woods at Sherwood Country Club in Thousand Oaks.

"Obviously, a huge blow for the tournament not to have Tiger here," McDowell said. "I feel very fortunate to receive the invite. It was a great opportunity for me."

McDowell decided to turn chances to improve his world ranking in this week's Australian Open or the first two events of the 2010 European Tour schedule in South Africa, starting next week. Now he is in position to make the top 50 in the world at the end of the year, ensure his place at Augusta and leave Harrington without a significant victory for the first time since 2005.

McDowell said: "I made the decision I wasn't going to go chasing the Top 50 in the world rankings. I had options in Australia this week, South Africa coming up here in the next couple of weeks. 

"I kind of made the decision I was just going to believe in my game and get myself in the Top 50 at the start of next year. Obviously this opportunity came along. Like I say, I don't really know where I need to finish tomorrow. I'm not really bothered. I'm just going to try and do my best tomorrow and see where that leaves me. 

"But like I said, it's obviously given me a little shot in the arm that I didn't think I was going to have. But yeah, if I can play well tomorrow, if I could get the job done, that would be unbelievable."

Harrington confessed that he was never comfortable on the course as he carded a two under par 70.

"I must have got out of bed on the wrong side or something," Harrington said. "Something wasn't right today. I played great yesterday, played good the first day, played horrible today. Who know what will happen tomorrow?

"I just have to hope that I get out of the right side of the bed tomorrow. It'll be as simple as that," he said.

Having become an inveterate reader of the golf coverage since the Tiger Woods affair exploded, Harrington is well aware that his only win this season came in the domestic Irish PGA at the European Club in July and that he hasn't won since the US PGA 16 months ago.

He said: "I just can't get too much into that. You know, that's not going to help me win tomorrow. If I don't win tomorrow, so be it, I kind of give it, the ah, well sort of thing. And if I do win tomorrow, I'll tell you it was very important. I'll wait for the results and we can decide how important it is for my year." 

As for his take on McDowell, Harrington explained that while you just don't know what you're going to get with the Ulsterman, he wasn't surprised to see his 2008 Ryder Cup team mate shoot 66.

Winner of the title at Sherwood in 2002, Harrington said: "Graeme's a really good player. He can be streaky. When he gets to playing well, he really can play very well ..... I could see players shoot 66, and Graeme's definitely well capable of doing it. He's done it many times in the past, so no real surprise there, no."

Meanwhile, the Belfast Telegraph reports that Darren Clarke has been seeing the former beauty queen and model agency boss Alison Campbell.

She said: "There’s no point denying it. Yes, Darren and I have been on a few dates and we’re having lots of fun. He’s a really nice guy and we get on very well, so who knows what might happen?

“But for now we’re happy to continue seeing each other and enjoying each other’s company.”