Paul Casey signalled his determination to win the Order of Merit in style with a brilliant first round in the Alfred Dunhill Links Championship in Scotland.

Casey carded a nine-under-par 63 at Kingsbarns - one of the three courses used for the pro-am event - to lead by one shot from Wales' Bradley Dredge and Sweden's Johan Edfors.

That left the Englishman 12 shots ahead of his nearest rival at the top of the money list, Ryder Cup team-mate David Howell, who struggled to a 75 after suffering a recurrence of a shoulder injury.

Casey, who could clinch the Order of Merit this week with a victory and suitable performances elsewhere, insisted he was keeping the issue at the back of his mind.

"I'm really not going to think about it," said the 29-year-old, who overtook Howell by winning the £1million first prize at the HSBC World Matchplay at Wentworth the week before the Ryder Cup.

"I would dearly love to win it and if it happens, it happens, but if it doesn't, it doesn't.

"But it would be a wonderful honour. I have achieved so many of my goals this year and feel very satisfied so, if I was to win, it would be brilliant. If not, then it doesn't matter as I've had a wonderful year anyway.

"I can't control what the other guys do. I have David behind me and a few other guys are very much in it."

Casey, who carded seven birdies and holed out from 80 yards on the sixth for an eagle, could only finish 56th out of 62 last week as the World Match Play and Ryder Cup took its toll.

"That's all it was and I couldn't control that," added Casey, who recorded only the fifth hole-in-one in Ryder Cup history at the K Club.

"I still feel tired but I went into today with a really good attitude and didn't expect too much. That's what I intend to do for the rest of the week.

"I'm not going to change the whole routine and go all serious just because I'm in front."

Casey is £80,000 ahead of Howell and £250,000 clear of Robert Karlsson, but the vast amounts of prize money on offer here and in the season-ending Volvo Masters at Valderrama means Karlsson (third), Henrik Stenson (fourth), Padraig Harrington (fifth) and Colin Montgomerie (seventh) are among those still in with a chance of topping the standings.

Harrington was the best placed of those after an opening 66 while Karlsson and Stenson both returned rounds of 68. Montgomerie - seeking a ninth Order of Merit title - could only manage a 73.

Howell said: "My body is tired, my mind is tired and although I'm trying to concentrate it's been very difficult. Because of the shoulder injury, I've come into it with no practice rounds and feel very unprepared.

"Paul's been playing great recently even though he had a bad week last week and lost a bit of momentum then."

Dredge's 64 at St Andrews established a new course record for the lengthened layout and could have been significantly better but for a double-bogey six on the 17th where he drove out of bounds.

"A lot of good players have played here over the years so to be the course record holder is pretty good," said Dredge, who cruised to an eight-shot victory in the Omega European Masters in Switzerland last month.

"After starting at the tenth, I was six under after seven holes but then carved it out of bounds on 17. I actually holed a good 12-foot putt for a six so walked off smiling!"

The Dunhill Links event sees each of the 168 professionals teamed up with an amateur.

The teams play one round at each of the courses over the first three days before the top 60 professionals and those tied for 60th place, together with the top 20 teams, compete in Sunday's final round.