O’Brien is bidding to win the St Leger for the fifth time in his career this season. The final British Classic of the year, which will be held on August 16, sees O’Brien’s Capri as the 7/2 joint-favourite with BoyleSports for the 1m6f contest at Doncaster. The three-year-old finished sixth in the Derby at Epsom earlier in the campaign but then was successful in the Irish equivalent just weeks later, where he finished ahead of Cracksman and his stablemate Wings of Eagles. The way the son of Galileo finished his race at the Curragh suggested a step up to the St Leger could see further improvement out of the colt. O’Brien’s last success in this race was with Leading Light in 2013. The Irish horse then went on to score in the Ascot Gold Cup the following season so he is likely to have a similar plan for Capri if he can come out on top at Doncaster. The leading challenge to Capri’s Classic bid, according to the betting, is Crystal Ocean. Sir Michael Stoute’s runner won the Group Three Gordon Stakes at Goodwood last month, his opening success at Group level. The lightly raced colt did not run in any of the other Classics in Great Britain or Ireland earlier in the season. Stoute has only won the St Leger once in his career and that was in 2008 when he trained Conduit to victory in the oldest British Classic. Champion Jockey Jim Crowley is set to partner Crystal Ocean for the first time after picking up the ride. One of the horses who goes into the St Leger with the best form this year is Defoe as Roger Varian’s runner has scored in his last four races, including the Group Three Geoffrey Freer Stakes. His latest success was over 1m5f, therefore he has no stamina doubts ahead of his Classic bid. The St Leger will be live on RTE at 15:35 in which it will be the fourth race on a packed card at Doncaster – which also features two Group Two races.