PERSISTENT rain has lashed Longchamp racecourse in the last 48 hours, throwing wide open today's Prix de l'Arc de Triomphe but presenting Gerald Mosse with his biggest chance of climbing back to the top since his surprise return from Hong Kong earlier this year.
Mosse rides the Aga Khan's Shemaka, the filly he partnered to a fine win in the French Oaks at Chantilly in June and one the stylish Frenchman believes will be ideally suited by the prevailing heavy going.
''Shemaka is spot on,'' Mosse said. ''I know she has never raced over a mile and a half before, but I am certain the trip will suit her, and so will the ground. The more rain to fall, the better she will run,'' he added.
Bookmakers Ladbrokes are offering the lightly-raced Shemaka at 10-1, with Pat Eddery's mount Wemyss Bight, the Irish Oaks winner, installed the 9-2 favourite, and Hernando, the French Derby winner to be partnered by Cash Asmussen, second elect at 5-1.
Michael Roberts, bidding for his sixth Group One victory in Sheik Mohammed's maroon and white silks this season, aboard Opera House, is no better than 8-1, while Intrepidity, the Epsom Oaks heroine representing last year's winning Arc combination of AndreFabre and Thierry Jarnet, can be backed at 9-1.
Mick Kinane is committed to Dermot Weld's mud-loving outsider Market Booster, offered by Ladbrokes at a Scrooge-like 40-1 when other bookies are going nearly three times those odds. When was the last time Kinane rode a 100-1 winner? The Arc is Europe's richest all-aged contest, in which 23 runners are due to face the starter this year.
The open nature of the race can be gauged by the fact that no individual horse - or traditional trial, for that matter - has had the word ''Arc'' stamped upon it this year. The going just makes it a greater puzzle.
Philip Robinson, the former dual-Hong Kong champion, is due to renew acquaintances with Bob's Return, his St Leger winner, but even taking into account that the colt seems to cope with soft ground better now than earlier in his career, he is not expected to handle a heavy surface. The 16-1 available should grow larger by the hour.
Another interesting runner from a Hong Kong angle is Urban Sea, who finished unplaced for Walter Swinburn in the Hong Kong International Cup last April when looking very much on the light side. She has won three races this year and finished second in the Prince of Wales's Stakes at Royal Ascot in June.
This time, Urban Sea is partnered by Eric Saint-Martin as Swinburn switches to Ezzoud, the shock winner of the Juddmonte International at York.
As much as Mosse might argue a convincing case for Shemaka, who is out of a half-sister to the dam of dual-Derby winner Shahrastani, the form book indicates that no matter how much promise the filly has shown, both Intrepidity and Wemyss Bight, who finished one-two respectively in the Prix Vermeille, have better credentials, at this stage.
And as Intrepidity has already won in heavy ground, she should be completely at home in the Arc and I expect her to give Sheik Mohammed his first taste of success in the great race.