Paul Casey was today on course to strengthen his position at the top of the Order of Merit in the Alfred Dunhill Links Championship in Scotland.

Casey has an £80,000 lead over Ryder Cup team-mate David Howell with just three events remaining — and was soon six shots ahead of his fellow Englishman in the opening round of the pro-am event played at St Andrews, Carnoustie and Kingsbarns.

Starting from the 10th at Kingsbarns, Casey birdied four of his first six holes to lie just two off the lead held by Mark Roe, Mikko Ilonen and Johan Edfors — with former Ryder Cup captain Sam Torrance in a large group a shot further back on five under.

In contrast Howell was two over par for the same stretch of holes as he struggled with the recurrence of a shoulder injury, the 31-year-old admitting only the prospect of winning the money list title ensured he was playing at all this week.

Although Casey holds the upper hand in the race to succeed Colin Montgomerie as European number one, the vast amounts of prize money on offer here and in the season-ending Volvo Masters at Valderrama means Ryder Cup stars Robert Karlsson (third), Henrik Stenson (fourth), Padraig Harrington (fifth) and Colin Montgomerie (seventh) are among those still in with a chance of topping the standings.

Karlsson trails Casey by £250,000. But the first prize this week is £427,000, and the 37-year-old made the perfect start to his opening round this morning — carrying on where he left off last week.

The 6ft 5in Swede, who carded a final round of 64 in the American Express World Championship on Sunday, opened with two birdies and added a third on the 16th to be out in 33.

A further birdie on the third drew him alongside Casey on four under par as the players took advantage of perfect scoring conditions. Stenson and Harrington were also four under after 12 and eight holes respectively, but Montgomerie was one over after nine.

The pro-am event sees each of the 168 professionals teamed up with an amateur partner.

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 at St Andrews.