Cheltenham Gold Cup winner Native River's trainer Colin Tizzard has described the victory as "unreal".
Ridden by jockey Richard Johnson, the 5-1 chance edged out favourite Might Bite by four-and-a-half lengths to give the Dorset trainer his maiden triumph in the race.
One year after finishing third, Native River wins the @TimicoGoldCup 🏆
— CheltenhamRacecourse (@CheltenhamRaces) March 16, 2018
And 18 years after his last win in the race, @dickyjohnson77 is on top of the world once again 🏆#TheFestival pic.twitter.com/WWKAXcd7to
Speaking to BBC Sport afterwards, Tizzard declared that the victory "means everything to everyone".
"It was unreal, wasn't it? To win the Cheltenham Gold Cup means everything to everyone's life. Let's not pretend it's not," he said.
"Richard Johnson galloped and jumped as fast as he could and the horse never let him down once. He just powered away. We've had a wonderful preparation and you think something could go wrong in the race, but it didn't.
"The Irish have been winning everything this week but Richard gave it that sort of ride. When Might Bite came beside him, Native River just flew over the last. He wasn't quite right after Cheltenham last year so we've stuck to the plan and it has come in.
"I never thought in my biggest dreams that I would win a Gold Cup."
Native River's victory means that King George VI Chase winner Might Bite failed to secure a historic Cheltenham Festival treble for trainer Nicky Henderson.
