A fascinating final week is on the cards as the European Tour comes to a close in Spain on Sunday. As always Club de Golf Valderrama will be a fitting venue for the Volvo Masters, where the European Order of Merit winner will be decided.

After a long European season four players remain in contention for the Order of Merit. Paul Casey (pictured) is favourite to take the title as he takes a ?218,185 lead into the event. However, with a ?666,660 first prize and a ?4,000,000 total purse, anything could happen. Padraig Harrington is Casey?s biggest threat but will need to improve on a disappointing missed cut last week. David Howell has led the Order of Merit for much of the season but a serious, recurring shoulder injury has threatened to ruin his chances. After a solid season Robert Karlsson is placed in fourth and requires a top-2 finish to give him a chance of topping the Order of Merit.

Casey undoubtedly takes the best form into the week even after a fortnight off at his home in the United States. His victory in the World Match Play Championship in September, which won him £1million, followed by his performance in the Ryder Cup have established him in the world?s top 20.

Harrington experienced a similar challenge to this in 2002, when he entered the Volvo Masters only £17,000 behind Retief Goosen. Harrington was unable to catch Goosen, hindered by a two shot penalty for repairing a pitch-mark when he was off the putting surface. This resulted in a second second place finish in the Order of Merit in as many seasons.

As one would expect there is an extremely strong field competing this week, as only the Top 60 in the Order of Merit are eligible to play. With the exception of Darren Clarke all of Europe?s victorious Ryder Cup side will be present, including defending champion Paul McGinley. Other notables include last week’s Mallorca Classic winner Niclas Fasth and the in-form 2004 champion, Ian Poulter.

Spanish hero and world number 9 Sergio Garcia begins the week as the bookmakers’ favourite to win the event, closely followed by world number 8 Luke Donald.

The home straight at Valderrama is perfect for providing added excitement. The par-5 17th in particular usually means that even the largest of leads on Sunday does not guarantee victory. With the added pressure of the Order of Merit we should be left with a memorable and fitting close to the European season.