Matt Henry, the gelding's apprentice rider, darted the 4-1 chance to the front approaching two furlongs out to beat Nothing Doing by a length and a quarter in the Foil Handicap Selling Stakes.
O'Sullivan, who was celebrating a long-range double, La Petite Fusee having won earlier yesterday afternoon at Southwell, has trained El Volador since the horse was three.
The trainer said: "He has won 10 on the Flat, the majority of those on the all-weather, and two over hurdles. We gave him a year off in 1994 when he jarred his shoulders, but he has been a good old servant."
The Stockbridge trainer Ken Cunningham-Brown passed the pounds 100,000 prize money total for the first time in a season when Village Native made all the running to take the second part of the Broadsword Auction Maiden Stakes under Darren Biggs.
After the French-bred colt had beaten Bearnaise, the 13-8 favourite, by a length and a quarter, Cunningham-Brown said the two-year-old would be going back to his native country later this month for a race yet to be decided upon.
The Hampshire handler has had a fine season, highlighted by Bold Effort's win in the pounds 39,000 William Hill Handicap at York in June.
But Cunningham-Brown's concentration inevitably now turns to jumping and in particular to novice steeplechaser, Dancing Paddy, who recorded excellent wins at Ascot and Ayr last season to confirm earlier promise.
"Dancing Paddy is due to make his first appearance of the new season in the First National Bank Gold Cup Chase at Ascot on Saturday week," the trainer said.Reuse content