Munster 23 Clermont Auvergne 13: The sense of relief was palpable at Thomond Park as Munster rescued their Heineken Cup season with a late flurry of scores. Trailing 13-11 with just four minutes on the clock, last gasp tries from Marcus Horan and Niall Ronan kept the defending champions in the competition.
There was plenty of pre-Christmas cheer among a capacity 26,000 crowd but Clermont Auvergne travelled to Limerick determined to spoil the party.
Despite missing captain Aurelien Rougerie (jaw) and prop Thomas Domingo (shoulder), the visitors could still select a team brimful of quality and so different to the makeshift one that lost 36-13 here last season.
Showing early abrasion and dominating territory, Vern Cotter's men settled quickly with Pierre Mignoni and Brock James combining well behind an athletic pack.
Munster took 12 minutes to get close to the Clermont 22 and O'Gara uncharacteristically missed his first shot at the posts, firing his 13th-minute penalty wide on the left.
The tension was obvious and it spilled over six minutes later when Clermont lock Jamie Cudmore threw a succession of punches at Paul O'Connell and the Munster captain, after initially drawing the touch judge's attention to the incident, sought retribution.
O'Connell saw yellow for using his fists while a clearly-ruffled Cudmore, who clashed in the aftermath with Donncha O'Callaghan, was sent off by referee Chris White.
Cotter's charges faced playing three-quarters of the match with 14 men but, although O'Gara was successful with the resulting penalty, Munster gave away a cheap three points off the restart, which James added his name to.
Using their numerical advantage, Munster began to find more space and a superb counter attack from Keith Earls ended with Doug Howlett being hauled down only metres from the whitewash.
O'Gara kicked Munster into a 6-3 lead with his second penalty but Clermont continued to look dangerous. A thumping Marius Joubert tackle produced a turnover and, but for a knock-on, Julien Malzieu would have been in open country.
However, Munster wrestled back the advantage and grabbed a timely try just before half-time. Number eight David Wallace, supported by Alan Quinlan off a close-range ruck, powered forward through three tackles to make the line and send the Irishmen into a 11-3 lead, with O'Gara failing to convert.
Determined to take the champions' scalp, Clermont Auvergne made a strong start to the second half with their seven-man pack producing some heroics. The French outfit starved Munster of possession and the hosts were spun into a slump, akin to the one that proved costly for them in last weekend's 25-19 loss at Stade Marcel Michelin.
James punished a Quinlan indiscretion with his second successful penalty and nerves jangled as both kickers missed penalty shots coming up to the hour.
Right on cue, deadly finisher Malzieu threw a spanner in the works. The Clermont winger blazed a trail down the left touchline and got over in the corner, after fending off both Barry Murphy and Earls.
James curled his conversion over for a 13-11 scoreline and Munster were staring at a rare European defeat on their home patch.
Napolioni Vonowale Nalaga barged his way forward and chased his own kick down, which could have led to a second Clermont try, but replacement Paul Warwick came to Munster's rescue.
Then, in a thrilling finish, Munster showed just why they are in the running for their third European title in four years. Tony McGahan's side needed a late O'Gara kick to see off Montauban in October but they bettered that here with a fantastic two-try comeback.
Inspired by sprightly replacement Peter Stringer and the lung-busting work of O'Connell, Munster spread the ball out to the right wing where a flicked pass from Lifeimi Mafi helped Horan burrow over past Mario Ledesma.
Television match official Graham Hughes confirmed the grounding but O'Gara pulled his conversion attempt.
There was more drama to come as only a minute from the finish, flanker Ronan spotted a mismatch with Davit Zirakashvili, chipped over the top and beat the prop for pace to score to the left of the posts.
O'Gara's conversion from wide out was good, taking his impressive European haul to 1,001 points and completing a fine comeback.
Munster: K Earls; D Howlett, B Murphy, L Mafi, I Dowling; R O'Gara, T O'Leary; M Horan, J Flannery, J Hayes, D O'Callaghan, P O'Connell [capt], A Quinlan, N Ronan, D Wallace.
Replacements: D Ryan for Quinlan 56 min; P Warwick for Murphy 61 min; T Buckley for Hayes 66 min; P Stringer for O'Leary 72 min.
ASM Clermont Auvergne: A Floch; J Malzieu, M Joubert, B Baby, N Vonowale Nalaga; B James, P Mignoni; L Emmanuelli, B Cabello, J Roux, J Cudmore, T Privat, J Bonnaire, A Audebert, E Vermeulen [capt]
Replacements: M Ledesma for Cabello half-time; D Zirakashvili for Roux half-time; S Bai for Baby 52 min; C Samson for Privat 67 min; E Etien for Vermeulen 72 min.
