Louis Oosthuizen leads Dunhill Links Championship

South African Oosthuizen won the Open Championship in 2010

Former Open champion Louis Oosthuizen fired a 66 to take a share of the lead among a host of low scores on day one of the Dunhill Links Championship.

The South African was joined by Northern Irishman Michael Hoey and two others, one shot ahead of a group of six players, including Graeme McDowell.

England's Lee Westwood and Scot Colin Montgomerie finished the day four under, with Luke Donald a shot back.

And US Open champion Rory McIlroy was not far off the pace on two under par.

The Dunhill Links Championship is played across three Scottish courses; Kingsbarns, Carnoustie and St Andrews, with a prize of £511,000 for the winner.

Kingsbarns had the lowest scores in the main, with 14 of the top 21 players seeing out their round in Fife.

Those included Oosthuizen, McDowell, Westwood and Montgomerie, as well as Englishman Tom Lewis, Germany's defending champion Martin Kaymer and Irishman Padraig Harrington, who all finished four under.

McDowell was delighted with his form after a difficult time since a sensational 2010 in which he won the US Open and holed the winning putt for Europe in the Ryder Cup.

"At the US PGA Championship [in August] things came to a head," McDowell said. "Myself and my caddie had to have a bit of a heart-to-heart as to what we were doing and what we needed to change.

"I've got more clarity of thought with my game, which excites me. At one point in August I really wasn't looking forward to a busy schedule at the end of the season."

Lewis was also positive looking ahead as he bids to round off a fine year - in which he shot the lowest round by an amateur at the Open with a 65 - by earning his full playing card for next year.

That would allow him to take part in the main events on next year's tour but, to do so, the 20-year-old has six more events this season to earn around £190,000.

Lewis said: "Rory [McIlroy] got his card in three starts and hopefully I can do as well as well.

"I've seen it [events like this] on TV and this is where I want to be."

Donald, too, played out his opening round at Kingsbarns as he aims to become the first player to finish top of both the PGA and European Tour prize money lists.

He leads Rory McIlroy by £1.4m in Europe's rankings but is only £44,000 clear of Webb Simpson in the United States.

Hoey enjoyed the best round of the day at St Andrews with six-under, while Scot Marc Warren fired the lowest round at Carnoustie - a five-under-par 67.

Open champion Darren Clarke endured a tricky day, however, finishing on one over par at Kingsbarns.