O'Connell was sent off shortly after coming on as a replacement
Munster had comeback man Paul O'Connell sent off as they consolidated their position at the top of Heineken Cup Pool Three with a win over Ospreys.
A Doug Howlett try and Ronan O'Gara penalty to two Dan Biggar penalties gave Munster an 8-6 half-time lead.
Tommy Bowe scored an early second-half try but David Wallace and Johne Murphy touched down before O'Connell saw red for a swinging arm on Jonathan Thomas.
O'Gara added two conversions and Biggar two penalties and a conversion.
Munster top the group on 10 points, with Ospreys now third on six points.
Biggar scored the opening points of the game in the second minute, knocking over a penalty after Munster were adjudged to have collapsed the scrum.
The home side responded in style when Tomas O'Leary took advantage of poor defending by Richard Fussell to cleverly kick the ball through for Howlett to gather and score in the corner, O'Gara missing the conversion.
Biggar kicked his second penalty of the game from in front of the posts to nudge Ospreys ahead and then O'Gara was off-target with penalty attempts in the 15th and 30th minutes.
Biggar missed with a kick at the posts four minutes later as both sides struggled to gain the ascendancy.
O'Gara eventually found his range in the final minute of the first half, landing a penalty to give his side the lead at the interval.
Ospreys began the second half strongly, Bowe running clear and touching down under the posts after intercepting an attempted pass from Sam Tuitupou to Keith Earls.
Biggar added the simple conversion to put the Ospreys five points clear.
The visitors had prop Paul James sin-binned for 10 minutes after infringing at a huge Munster scrum and soon after Munster received a further boost with the introduction of Ireland and Lions lock O'Connell.
Wallace bundled his way over the line for Munster's second try of the game with help from fellow forwards James Coughlan and Mick O'Driscoll in the 59th minute, O'Gara converting.
Murphy took further advantage of the extra man four minutes later by crossing the Ospreys line after O'Leary picked up a loose ball and passed for the winger to race over in the corner.
O'Gara made no mistake with the conversion to increase his side's advantage to nine points.
Biggar then reduced his side's deficit with a well struck penalty and a minute later O'Connell was sent-off, only 10 minutes after coming on as a replacement, following a wild swing into the face of Thomas with his arm.
Barry Davies slotted the resultant penalty between the posts to reduce the Welsh side's deficit to six points but Ospreys were unable to make further inroads and had to settle for a losing bonus point.
A crucial late Alan Quinlan turnover killed off any lingering Ospreys hopes.
Munster coach Tony McGahan: "[On seeing O'Connell's red card] I was hoping I was colour blind! But unfortunately my eyesight is good enough because I'm still young.
"We had a brief look at it. We really haven't looked at it in enough depth to give any real comment.
"What we saw was the same as what everyone else saw, a reaction to [Jonathan Thomas] holding onto the jersey. I'll have to give it a bit more thought.
"It doesn't serve any purpose for us to get caught up in that while the game was going on. I was shocked really, but we just had to get on and deal with it."
Ospreys forwards coach Jonathan Humphreys: "First of all, Paul O'Connell is not a dirty player by any stretch of the imagination.
"A very similar thing happened to Gavin Henson for a similar incident and unfortunately he got 10 weeks for that.
"We have a lot of admiration for Paul as a player. He's a very iconic figure here, so it's very disappointing for him. He could miss a large chunk of the season now."
Munster: P Warwick; D Howlett, K Earls, S Tuitupou, J Murphy; R O'Gara, T O'Leary; W du Preez, D Varley, T Buckley; D O'Callaghan, M O'Driscoll; J Coughlan, D Wallace, D Leamy (capt) Replacements: J Hayes for Buckley (68), P O'Connell for O'Driscoll (60), A Quinlan for Coughlan (60), L Mafi for Earls (75), Denis Hurley for Warwick (71).
Not used: M Sherry, Darragh Hurley, P Stringer.
Ospreys: Barry Davies; Tommy Bowe, Andrew Bishop, James Hook, Richard Fussell; Dan Biggar, Mike Phillips; Paul James, Richard Hibbard, Adam Jones, Ryan Jones, Alun Wyn Jones (capt), Jerry Collins, Marty Holah, Jonathan Thomas. Replacements: Mefin Davies for Hibbard (50), Duncan Jones for James (74), Ian Gough for Thomas (72), Sonny Parker for Bishop (74), Nikki Walker, Collins for D Jones (68).
Not used: Craig Mitchell, Justin Tipuric, Jamie Nutbrown.
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