Riverside Theatre got up in the final strides to give Nicky Henderson a sixth winner at the Cheltenham Festival meeting with a dramatic victory in a thrilling Ryanair Chase.
Barry Geraghty galvanised the eight-year-old, part-owned by actor Jimmy Nesbitt, to deny Albertas Run a third successive win in the race after a pulsating battle up the run-in.
Riverside Theatre, the 7-2 favourite, snatched the spoils by half a length from Albertas Run, who had set sail for home with six fences remaining, with Medermit another half a length away in third after a struggle that could have gone to any of them.
Geraghty said: "It was hard work. I never travelled and he missed a good few (fences), but he's game. I threw him at the last four fences and he kept coming up. I was beaten everywhere. I was a bit tight for room because he wasn't travelling, but every time I dug into him he found more.
"I was trying to keep count (of the whip) and I hope I'm all right. He's very classy. It's unbelievable training to bring him back from a year off to win two Grade Ones."
Nesbitt added: "I just can't believe the ride Barry gave him, and Nicky has done such an incredible job to bring him back like he has. The training performance at Ascot was extraordinary, but to have him in that nick today - to have that courage and battle like he did is incredible."
Henderson said: "In fairness that was some great ride. I don't think either of us was enjoying that a lot and I don't think Barry was either as it didn't look very likely all the way. They were always travelling a gear higher than he wanted to be in. That was some ride to get him home."
Jonjo O'Neill said of Albertas Run: "He's run a cracking race and we're thrilled to bits with him. The ground was maybe a bit on the dead side and AP (McCoy) said there was one fence on the top of the hill that he didn't really fly, he didn't miss it but just didn't make up as much ground as he might have done.
"He's a great horse to train and I wish I had a yard full of horses like him. I thought we were in with a chance and Riverside Theatre was on and off the bridle, but Barry gave his horse a great ride, as did AP, but he stayed on. He'll probably go to Aintree if he's OK."
Noel Williams, Alan King's assistant trainer, said of Medermit: "He's run a great race. We'd been thinking about this or the Gold Cup, he stays this (two-mile-five) trip well and I think he'll be worth running over three miles now. He's so unlucky not to win here, but he's always there or thereabouts."