Munster (0) 28
Tries: Varley, Ronan, Earls, D Hurley Cons: O'Gara (4)
London Irish (0) 14
Tries: Mapasua, Tagicakibau Cons: Bowden, Lamb
Keith Earls scores a try for Munster in the second half
Munster scored three tries in the final 10 minutes to shake off London Irish and earn a bonus-point win that could see them move into the Challenge Cup.
Irish, with tries from captain Seilala Mapusua and Sailosi Tagicakibau, were 14-7 ahead with 12 minutes left.
But Munster, out of quarter-final contention, hit back decisively with late tries from Niall Ronan, Keith Earls and replacement Darragh Hurley.
Hooker Damien Varley had earlier scored Munster's first try.
That followed a scoreless first half in Limerick, with Munster unable to convert their early territory into points.
London Irish had prop Faan Rautenbach sin-binned for stamping on David Wallace at a ruck.
In the second half, Varley plunged over for a deserved try after a forceful maul and Ronan O'Gara nailed the conversion from the right of the posts.
Mapusua's try came after Tomas O'Leary's clearance kick was charged down by Jamie Gibson and the Samoan touched down in the left corner.
Bowden followed up with the conversion to make it 7-7 on the hour and Irish were suddenly forcing the pace.
In the 67th minute, Mapusua did brilliantly to dink a kick ahead, gather the ball at pace and link with Topsy Ojo, whose pass out of the tackle set up Tagicakibau for an easy run-in past O'Gara.
Replacement Ryan Lamb added the difficult conversion, and Irish were suddenly on the verge of becoming only the second team to beat Munster in a Heineken Cup tie at Thomond Park.
Munster, helped by a yellow card for Gibson, hit back with their second try when flanker Ronan picked up from a ruck and dived over with O'Gara converting.
Three minutes later, they had another try. Paul O'Connell stole a line-out and rampaged through the middle, and O'Gara's superbly-weighted kick to the corner was gleefully finished off by Earls.
O'Gara swung over the conversion and did likewise in injury-time after prop Hurley had powered over.
Their barnstorming finish means Munster - depending on results of Sunday's matches - could clinch one of the three quarter-final places on offer in the second-tier Amlin Challenge Cup.
Munster coach Tony McGahan: "The Amlin Challenge Cup certainly wasn't our driving force. We didn't speak about it or hang our hat on it. Our driving force was getting a result here at home and all that that entails.
"We were playing for our lives really. We were playing at home with a tremendous record, which has been gained over a long period of time with a lot of guts, spirit and passion.
"We certainly weren't ready to give that up. With our record at home it was important that we gave a performance.
"It's been a tough week and although this result doesn't mask previous performances on the road, it certainly leaves a lot to build on."
London Irish coach Toby Booth: "I wasn't actually at the draw [for the Heineken Cup pool stages]. I was on holidays and when the message came through, I thought I had been drinking.
"Munster were top seeds in tier one, the Ospreys were seeded top of tier two, we were seeded top of tier three, and Toulon were top seeds of tier four.
"Mathematically you can't get any tougher than that. Whether that is right or wrong, that is the situation. That is the luck of the draw I'm afraid."
Munster: J Murphy, Howlett, Earls, Mafi, D Hurley, O'Gara, O'Leary; Du Preez, Varley, Hayes, O'Driscoll, O'Connell, Wallace, Ronan, Leamy.
Replacements: Deasy for J Murphy (62), Stringer for O'Leary (67), Hurley for du Preez (71), Sherry for Varley (71), Buckley for Hayes (40), O'Callaghan for O'Driscoll (62), Coughlan for Wallace (69).
Not used: Gleeson.
London Irish: Ojo, Thompstone, Seveali'i, Mapusua, Tagicakibau, Bowden, Allinson; Corbisiero, Buckland, Rautenbach, Kennedy, Garvey, Stowers, Gibson, Hala'ufia.
Replacements: Lamb for Bowden (62), Hodgson for Allinson (62), Murphy for Corbisiero (75), Ion for Rautenbach (56), Roche for Kennedy (78), Thorpe for Stowers (56).
Not used: Blaney, Watson.
Ref: Peter Allan (Scotland)