O'Connell's decision not to kick an easy penalty may have cost Munster
Munster 0 (6)
Pens: O'Gara 2
Leicester 13 (8)
Tries: Murphy, Smith
Leicester created history as they became the first team to beat Munster in the Heineken Cup at Thomond Park, topping Pool Four in the process.
Ian Humphreys and Ronan O'Gara landed a penalty apiece before Geordan Murphy's try put the Tigers 8-3 in front.
O'Gara cut the gap to 8-6 at the break but the European champions spurned a penalty in the second half and Ollie Smith's try sealed Leicester's win.
Munster still made the last eight as one of the two best runners-up.
From the moment Leicester centre Dan Hipkiss sliced through the Munster line from deep in his own 22 after just 30 seconds it was clear the Tigers were up for it.
And they took the lead after three minutes when Humphreys, younger brother of O'Gara's long-time rival for the Ireland number 10 shirt David, landed a penalty.
O'Gara missed a long-range kick after 11 minutes but the Munster number 10 was soon on target from in front of the posts after he had cut through from an inside pass.
However, Leicester were back in front within three minutes, claiming the first try of the night as Lewis Moody's fine pass gave Murphy the chance to finish in style.
Both teams were defying the wet and windy conditions to produce some fine rugby but as the game passed the half hour mark the rain began to hammer down.
O'Gara gave the crowd something to cheer when he judged the wind perfectly to trim the gap to two points with a penalty right on the stroke of half-time.
Leicester had held the upper hand physically during the first half and although Munster showed signs straight after the break of getting to grips with the visitors, the Leicester pack reasserted itself.
The Tigers eight earned Humphreys a chance to stretch the lead but he was off target with a 55th-minute penalty.
Five minutes later Munster bafflingly spurned the chance to take a kickable penalty in favour of a scrum and they immediately lost possession when the Leicester pack produced a massive shove to turn them.
It was a decisive moment and one that captain Paul O'Connell will regret for a long time.
Leicester re-established control and they stretched seven points clear when Smith stepped inside the cover and just managed to get the ball down for an unconverted try.
Munster launched a desperate late fightback but their best chance went when Leicester again disrupted an attacking scrum, and the Irish side will now have to win on the road in the last eight as they seek to defend their title.
Leicester captain Martin Corry:
"It is an incredibly special feeling. "We went out there and performed. Every player stood up to the challenge, our mentality had been right throughout the week.
"It is a fantastic place to come and play rugby, and I thought we showed in the first 10 minutes that we were not going to be intimidated.
"Our scrummage was fantastic, and Ian Humphreys really stepped up. Your number 10 is key to the show, and he had the confidence to back himself.
"This is a huge win for us. The atmosphere in the dressing room is something special, and you realise that these are the moments to savour."
Munster fly-half Ronan O'Gara:
"It is obviously hugely disappointing for us, but the better team won. They talked it up but they walked the walk.
"Leicester were hugely dominant up front - their pack performance was terrific - but there are two ways we can go now.
"You can just sit down or you can go away, learn the lessons and then put up a real fight. I know which option we will be taking."
Munster: Payne; Kelly, Murphy, Mafi, Dowling, O'Gara, Stringer, Horan, Sheahan, Hayes, O'Callaghan, O'Connell, M O'Driscoll, D Wallace, Leamy.
Replacements: Flannery, Pucciariello, Coughlan, Foley, O'Leary, Manning, Cullen.
Leicester: Murphy; Rabeni, Hipkiss, Gibson, A Tuilagi; I Humphreys, Ellis; Castrogiovanni, Chuter, White, Cullen, Deacon, Moody, Jennings, Corry (capt)
Replacements: Buckland, Ayerza, Kay, Crane, F Murphy, Smith, Vesty