Duke Of Marmalade can round off a brilliant unbeaten season in Europe by winning the £3.1 million Qatar Prix de l'Arc de Triomphe at Longchamp on Sunday.

Aidan O'Brien's superstar has bagged five of the most prestigious Group 1's on the continent this year and, if anything, looks better now than at any point during the season.

Four of those triumphs were on the four-year-old's preferred quick ground and there have been doubts about Duke Of Marmalade should the going turn testing.

However, soft conditions didn't stop him on his 2008 debut at Longchamp and the current good going will suit.

Kieren Fallon, formerly No1 at Ballydoyle, believes Aidan O'Brien's other great hope Soldier Of Fortune will fare best of the pair but, with respect to the former champion jockey, he only rode Duke Of Marmalade once and that was long before he strengthened up into a champion racehorse.

Duke Of Marmalade has taken virtually the same route Dylan Thomas did last year en route to winning the Arc for the Ballydoyle team, but missing last month's Irish Champion Stakes due to heavy ground could prove to be a blessing in disguise as the son of Danehill will be relatively fresh on Sunday.

The Aga Khan's unbeaten filly Zarkava is a very warm favourite with the bookmakers on the back of some visually stunning performances, most notably when winning the Prix Vermeille last month.

However, it should be noted that not only will this be a first encounter with the boys, but no filly has won the Vermeille and the Arc since Three Troikas in 1978.

It is a task of almost Herculean proportions for a filly to win the Arc with Urban Sea being the last in 1993, with the Aga Khan's Akiyda being the last three-year-old filly to succeed in 1992.

Without question the most influential trial for the Arc is the Prix Niel, which has provided no fewer than 10 of the last 14 winners and this year's victor Vision D'Etat also won the French Derby.

But it is also worth noting that only one of the 19 rivals Vision D'Etat beat in the Prix du Jockey Club has won a race since.

The form of Eric Libaud's runner isn't anything like as strong as Duke Of Marmalade or Zarkava.

Soldier Of Fortune went into the race last year on the back of two fine wins, but was well held and nothing suggests he has improved this year.

Youmzain looks the best of the English judged on a narrow defeat last year and Mick Channon's five-year-old is sure to figure at the business end again.

Dylan Thomas held off Youmzain 12 months ago and Duke Of Marmalade looks set to make it a double for O'Brien and be the toast of Paris on Sunday.