Two of the better horses racing in Europe, Alpha Centauri and Saxon Warrior, were retired Sunday after sustaining injuries in Saturday races at Leopardstown in Ireland. Alpha Centauri suffered a shocking defeat in the Matron Stakes, where she was an odds-on favorite, and came out of the race with a fracture in her right-front fetlock, according to overseas reports. Alpha Centauri took two obviously bad steps in deep stretch while trying to run down the victorious Laurens in the Matron. A huge, charismatic gray filly, the 3-year-old Alpha Centauri, who had the Breeders’ Cup Mile on her agenda this fall, was bred and owned by the Niarchos family and trained in Ireland by Jessica Harrington. By Mastercraftsman and out of Alpha Lupi, by Rahy, she won the Irish 1000 Guineas, the Coronation Stakes, the Falmouth Stakes, and the Jacques Le Marois – all Group 1 miles – before her loss and injury Saturday. Saxon Warrior engaged the victorious Roaring Lion in an epic stretch duel, coming up a neck short in the Group 1 Irish Champion Stakes on Saturday, a race that has turned out to be his career finale. Trainer Aidan O’Brien told overseas reporters Sunday that Saxon Warrior had emerged from the race with a tendon lesion and had been retired. Europe’s best 2-year-old last year, Saxon Warrior won the English 2000 Guineas by 1 1/2 lengths to start his 3-year-old season, and though that would prove his only victory this year, Saxon Warrior confirmed his high-level ability with a close second to Roaring Lion in the Group 1 Coral-Eclipse Stakes and again in Saturday’s race. Saxon Warrior, a winner in four of his nine starts, is by Deep Impact and out of Maybe, by Galileo.