Ireland's Kevin O'Brien hit the fastest hundred in World Cup history to sentence shell-shocked England to an astounding three-wicket defeat at the M Chinnaswamy Stadium.
O'Brien (113) came to the crease when damage limitation seemed the best his team could hope for, after they lost three wickets for eight runs to falter to 111 for five in apparently vain pursuit of 327 for eight.
But he responded with an innings of immense power, smashing six sixes and 13 fours in a 50-ball hundred and dominating a stand of 162 in 17 overs with Alex Cusack (47).
No one in the England attack was safe, with Graeme Swann (three for 47) the lucky one that he managed to complete his full 10-over allocation before O'Brien began his assault in earnest.
England did not help themselves, dropping five catches in all, including O'Brien and Cusack once each.
In the end even O'Brien's run-out, trying to scamper a second run at the start of the 49th over, could not stop Ireland getting home with five balls to spare.
After O'Brien had very nearly finished England off, John Mooney clipped the winning four to midwicket in company with Trent Johnston.
Jonathan Trott (92) and Ian Bell (81) had been England's main batting contributors, the former also bagging a place in cricket history as the joint-quickest batsman to 1,000 one-day international runs.
But he was relegated from headline to footnote by O'Brien's unexpected heroics.