Liam Treadwell landed his most high-profile success since steering Mon Mome home in the Grand National as The Last Derby caused a 33-1 upset in the United House Gold Cup at Ascot.The five-year-old was Irish trainer Eoin Griffin's second runner at the track after Sanglote suffered a fatal fall in the previous race.Treadwell allowed his mount to warm to the task and produced him to lead jumping the penultimate obstacle and they were five lengths too strong for Aimigayle, with Shining Gale staying on nicely for third.Griffin said: "We have always thought a lot of him and two and a half miles at Tipperary last time was a bit sharp for him. Barry Geraghty suggested we stepped him up in trip. I was then flicking through the calendar and saw this race and decided to give it a go."He jumps efficiently rather than exuberantly and Liam gave him a brilliant ride."The winner is engaged in the Paddy Power Gold Cup at Cheltenham in two weeks' time and the sponsors trimmed him to 16-1 from 33s.Griffin added: "It might come a bit soon for him but we will get him home and see how he is before making a decision."Treadwell said: "That was the first time I had met Mr Griffin and I hope I meet him again! We were almost flat out for the first mile so I didn't want to hurry him."The further we went the happier I was and he has outstayed them. These big wins are few and far between. It has been a slow start to the season but I'll settle for this."