Simon Dyson drives off the 12th tee at Adare Manor on Thursday

England's Simon Dyson shot a 68 which left him in a four-strong group at the top of the Irish Open leaderboard after day one at Adare Manor in Limerick.

Dyson, who has two tour wins, was joined on four under by Swedes Peter Gustafsson, Peter Hanson and Christian Nilsson plus Argentine Andres Romero.

South Africans James Kingston and Louis Oosthuizen are one shot behind.

Last week's Andalucia Open winner Lee Westwood fired a steady 71 while Padraig Harrington shot an opening 73.

Dyson played on the victorious Walker Cup team of 1999, which also featured the likes of Ryder Cup stars Luke Donald and Paul Casey.

The 29-year-old from York then won the Asian Tour Order of Merit in 2000 but it took until the Indonesia Open in Jakarta last year for him to win on the European Tour.

I think they've lengthened it for the sake of it Lee Westwood

He followed that with victory in the KLM Open in August and has five top 10s to his credit already this season.

Dyson said that his decision to take his career more seriously - following the example of his friends Nick Dougherty and Kenneth Ferrie - has paid dividends over the last 12 months.

"My dad was always on at me because he knew I wasn't putting all of my time into being the best player that I could be," said Dyson.

"Then Nick and Ken just changed their attitudes. Nick was the one I used to go out with and all of a sudden he's going to the gym and earning a million quid a year and I thought 'I want a bit of that.'"

Westwood is in contention for back-to-back wins following an opening 71, but the 34-year-old was not too enamoured with the changes to the course.

"I think they've lengthened it for the sake of it. The new tees on the 11th and ninth are unnecessary and if they do get a 30mph wind it could make us look a bit daft," said the world number 48.

At 7,453 yards, Adare Manor is the longest course in Irish Open history, and the fifth longest to be used for a European Tour event.

But it had to be shortened by 246 yards on Thursday to help players cope with the penal rough and forecasted strong winds - which failed to materialise.

Dyson and 2005 Spanish Open champion Hanson were the only players to keep a bogey off their cards.