LONGCHAMP, PARIS // The master having to face the pupil is a well-known storyline, but rarely has it been played out under more scrutiny, and for higher stakes, than in tonight's Prix de l'Arc de Triomphe. Frankie Dettori will walk out to the parade ring ahead of his ride on Camelot sporting the purple and white colours of Derrick Smith, one of a trio of men behind the global breeding operation of Coolmore stud that powers Aidan O'Brien's Ballydoyle yard in Ireland. The Coolmore breeding organisation consistently has proved to be the fiercest competitor to Darley, the worldwide breeding business owned by <a href="gopher://topicL3RoZW5hdGlvbmFsL1Blb3BsZS9MZWFkZXJzIGFuZCBwb2xpdGljaWFucy9VQUUgcnVsZXJzL1NoZWlraCBNb2hhbW1lZCBiaW4gUmFzaGlk" inlink="topic::L3RoZW5hdGlvbmFsL1Blb3BsZS9MZWFkZXJzIGFuZCBwb2xpdGljaWFucy9VQUUgcnVsZXJzL1NoZWlraCBNb2hhbW1lZCBiaW4gUmFzaGlk">Sheikh Mohammed Bin Rashid</a>, Vice President of the UAE and Ruler of Dubai. Not far away from the Coolmore huddle will stand Mickael Barzalona, Dettori's supposed understudy who will ride Masterstroke in the silks of <a href="gopher://topicL3RoZW5hdGlvbmFsL09yZ2FuaXNhdGlvbnMvU3BvcnRzIHRlYW1zL0dvZG9scGhpbg==" inlink="topic::L3RoZW5hdGlvbmFsL09yZ2FuaXNhdGlvbnMvU3BvcnRzIHRlYW1zL0dvZG9scGhpbg==">Godolphin</a> France. Dettori has often ridden against Barzalona, who beat him into third when partnering Enkce to defeat Camelot in the English St Leger last month, but this will be the first time Dettori has had held a leading chance to deny his own team in the world's most valuable turf race. Dettori last got the leg up aboard an O'Brien-trained horse in the 2005 English St Leger. The Italian had been earmarked to ride in Ireland in preference to riding at Goodwood for his employers but jumped ship to successfully partner Scorpion at Doncaster. Dettori had to apologise to Sheikh Mohammed that time. As an illustration of how he feels about his current position within Godolphin, the Dubai-based organisation reportedly found out their flagship rider was to partner Camelot by text message. Dettori was recruited to Godolphin in 1994. Barzalona and Silvestre De Sousa came into the fold this season, and Dettori's role as first rider has been eroded ever since. Although it may not have seemed significant at the time, Dettori's position was clear when in the Queen Anne Stakes at Royal Ascot in June Barzalona represented Godolphin by riding Helmet, a horse he had never ridden before. Dettori was left to finish last on Worthadd, trained by Sir Mark Prescott. With Barzalona earmarked to ride Masterstroke, having partnered the three-year-old on debut last season, it clear that Dettori, who was riding overnight at Belmont Park in America, no longer has any more standing than Barzalona, or indeed De Sousa. For O'Brien, it was an easy decision to make. His son, Joseph, could not make the weight, and among the 18 riders in the race today, Dettori's CV outstrips them all. The 41 year old Italian boasts three victories in Europe's middle-distance showpiece, all of which were for Saeed Bin Suroor. He thrust Lammtarra to victory in 1995 before running away with the Arc on Sakhee in 2001. Dettori showed his versatility when coming from behind on Marienbard 12 months later. Camelot will be Dettori's 25th consecutive ride in the world's most valuable turf race, which means his first ride in the 12-furlong contest came before Barzalona was even born. Camelot is generally regarded as the likeliest winner of the 91st running of the Arc, but Masterstoke has been trained to the minute by Andre Fabre, who has sent out seven winners of the race. If Barzalona can take a pull from his wide draw in gate 17, track the field into the false straight and then get some luck in-running as the 18 runners fan out, master and pupil could well come together in the final furlong. Then the world, and the two jockeys, will hold their breath, and wait for the drama to play itself out to the finish line and beyond. Follow us