SHANGHAI - Rio de Janeiro will stage a "successful" Olympics, London 2012's chief organiser Sebastian Coe told AFP Saturday after concerns over preparations in the Brazilian city were raised by the IOC. Coe was speaking after International Olympic Committee vice-president John Coates in April criticised the Rio preparations as "the worst that I've experienced" in 40 years of being involved with the Olympics. Coates later backtracked on his comments, saying he believed Rio could still deliver "an excellent Games" but that "time is of the essence". Coe , the former head of The London Organising Committee of the Olympic and Paralympic Games, told AFP: "This is hard. I know this. No city is ever challenged in the way that it is when you deliver a Games, and I know that from experience.–AFP