Heavyweight World Champion Andy Ruiz Jr has been knocked out…by the iconic venue in Saudi Arabia where the Clash On The Dunes, his colossal rematch with Anthony Joshua, is set to take place.The American-Mexican fighter – known as 'The Destroyer' - toured the custom-built Diriyah Arena in the heart of the UNESCO World Heritage site ahead of the epic bout on December 7.   The 15,000-seater stadium has been constructed in the ancient remains of Saudi Arabia’s first capital, a place fittingly known as the ‘home of kings and heroes’.   Touring the Diriyah Arena, Andy Ruiz said: “It’s amazing man, it’s crazy how they built everything in a month and a half. It’s amazing to be fighting over here, it’s going to be really historic and I’m planning to make history over here.”   The World Champion first visited Diriyah for the official launch press conference in September, but since then 175 workers have created the arena in the 10,000 sq m site using 295 tonnes of steel.Ruiz said: “It’s a lot different. When I first got here none of this was here so it’s unbelievable. All the workers and all the people who have put their efforts in, their designs in, this event and this arena is just something amazing.”   Ruiz arrived in the Kingdom early Monday morning to set up his training camp ahead of his rematch with Joshua, with the US boxer determined to keep hold of the WBO, WBA, IBF and IBO belts he snatched from the Briton when they faced off in New York earlier this year.   “Right now, we are meditating, we are preparing, we are getting sharper in the ring and training as well. We are visualising the fight and becoming victorious,” said Ruiz.   “To all my fans please come and support me, it’s going to be a huge fight, it’s the Clash On The Dunes. We are two big guys fighting each other looking to be the Heavyweight Champion of the World.“He’s trying to take my belts away so I’m going to do everything that’s possible to win and I’m going to do it for all my people.   “They can expect to see someone who is not giving up and doing everything possible to win, God willing we are going to take this victory.”