Bookmakers were firmly in the driving seat after an enthralling day one at the Festival.
The first five favourites were turned over starting with a shock defeat for Dunguib in the opening Spinal Research Novices' Hurdle.
The Irish challenger had been seen as the banker of the entire four days for many punters and his defeat at 4/5 had the layers jumping for joy.
A string of further reverses followed with Chief Dan George's victory at 33/1 in the William Hill Trophy proving to be a skinner for most bookies.
"Chief Dan George's win was a satchel-buster," remarked David Williams of Ladbrokes.
A market leader finally obliged when Quevega (6/4) landed the David Nicholson Mares' Hurdle for the second year running, but it came too late to save the punters from a 5/1 drubbing.
"A victory for Dunguib would've been unthinkable but his defeat in the first kick-started a great day for the layers," said totesport spokesman George Primarolo.
Hayley O'Connor, of Ladbrokes, commented: "Dunguib's defeat was a God-send. The massive Irish plunge came entirely as we'd expected."
An estimated £10million was lost by punters on Dunguib as the layers amassed a total of £30m on a great first day for them.
The trend continued with defeats for Captain Cee Bee, The Package and the gambled-on Go Native all adding to the punters' woes.
The latter was a big disappointment in the big race of the day, the Smurfit Kappa Champion Hurdle in which success for 9/1 shot Binocular was also a good one for bookmakers.
Ladbrokes' Williams said: "Binocular was a smashing result in the big race. He'd slipped off the radar with his troubled build-up to the race and we were cheering him home. It came on the back of three great results and helped seal a winning start to the Festival for the bookies."
David Hood, spokesman for William Hill, said: "It's too early to get carried away but we've built up a hefty bank to go to war with over the remaining three days.
"Punters will lick their wounds tonight, then return refreshed tomorrow looking for every opportunity to level the score. We still fear the hotpot trio of Master Minded, Big Buck's and Kauto Star."
Betfred boss Fred Done added: "If it was a boxing match the towel would have been thrown in well before the lucky last. It definitely finished 5-1 to the bookies and it's one of the best first days I can remember."