Paul O'Connell's Heineken Cup comeback lasted barely 10 minutes as he was sent off in Munster's absorbing 22-16 Pool 3 victory over the Ospreys at Thomond Park.
Referee Christophe Berdos reached for his red card in the 70th minute after Ireland lock O'Connell, introduced on the hour mark as he continues his return from a long injury lay-off, was seen swinging his right arm into the face of Jonathan Thomas as he held him back.
Ronan O'Gara's penalty gave Munster an 8-6 half-time advantage before Tommy Bowe's 42nd-minute interception try had the Ospreys 13-8 in front but while Paul James was in the sin-bin, Munster's David Wallace and Johne Murphy crossed for converted tries. Dan Biggar closed the gap to six points before the dismissal of replacement O'Connell.
Biggar stroked over a second-minute penalty but poor defending from Richard Fussell, filling on for the injured Shane Williams, allowed Doug Howlett in for his third try in two pool games. Fussell was caught far too flat as Tomas O'Leary threaded through a perfectly weighted kick and Howlett raced up to gather and score in the corner.
O'Gara's missed conversion was followed by an immediate response from the Ospreys, with Biggar slotting a second penalty but O'Gara responded with a kick of his own.
Howlett found space in midfield and Damien Varley rumbled up to five metres from the try-line. The Ospreys held out and just when it looked like the hosts would convert an overlap on the left, Bowe gobbled up Sam Tuitupou's loose pass inside the 22 and broke clear to score under the posts. Biggar's simple conversion put five points between the sides.
Support from James Coughlan and Mick O'Driscoll helped Wallace muscle his way over the line from close range. The extras from O'Gara moved Munster back ahead.
With the Ospreys down to 14 men, a wayward up-and-under from Biggar broke for O'Leary to set up Murphy for a well-taken try, to the left of the posts which O'Gara converted.
But Munster had a rocky road to the final whistle, a scrum infringement allowing Biggar to boot the Ospreys to a losing bonus point.
The off-the-ball incident involving O'Connell, who is just back from a long-term groin injury, was then followed by a missed 54-metre penalty from Barry Davies, as the sides played out a scrappy finish.