McMahon off the mark on Rio Rio Treasure quickened up impressively to make a winning debut in the bumper at Listowel, giving Aubrey McMahon a winner on just his second ride. The Captain Rio filly, owned by the jockey's grand-mother Madeline, was held up in the early stages before making a move turning for home. She found a nice turn of foot to hit the front at the furlong pole and kept on strongly in the closing stages to post a three-length winning margin over Exxaro. 16-year-old McMahon is son of well known bookmaker and punter Luke McMahon who said afterwards:- “She's very small and Aubrey suited her taking 7lb off. He's been riding her out for a while. He was very cool on her and I'm very proud of him. “He's been riding out the last two summers for Willie and he recommended that this horse would be ideal for him to start off with.” The winning jockey later added:- “I'll never forget that. On my second ride to ride a winner is magic. “I thought going down the back I had a chance but she was green and looking around a bit. “Turning into the straight when she started to quicken I thought she had a good chance of winning and when she hit the front she galloped well to the line.” The winner had been easy to back returning 7/1 having been as short as 7/2 this morning. Ange D'Or Javilex was sent off the well-backed 11/4 favourite (8/1 in morning) and finished third. (Additional reporting by Alan Magee)