A much improved performance, a stunning display by fly-half Ronan O'Gara and a victory to keep Munster's European ambitions alive but they owe a great deal to Perpignan indiscipline as the French champions let a famous Heineken Cup win slip from their grasp at a nervously energised Thomond Park last night.
O'Gara produced a brilliant all-round display, showing the control and poise that forged his reputation while kicking all of Munster's points via seven penalties and a drop goal.
The Munster coach Tony McGahan said: "I thought Ronan O'Gara was outstanding tonight. He has been outstanding even since he came back into the camp after the autumn internationals.
"He is a tremendously strong-willed person," McGahan added. "He did not lose his belief and we certainly did not lose our belief in him."
Although Perpignan's smothering defence did not open many avenues for exploration, there was far greater cohesion to Munster's back play with Keith Earls back in the centre next to Lifeimi Mafi and Denis Hurley putting in a powerful display on the wing.
The forwards went well as a unit also, with Alan Quinlan and his back row having big games and the front five battling away all night. They had to for Perpignan are not French champions for nothing and, for all Munster's improvement, next weekend's rematch is a daunting challenge.
Munster opened with a fury that reflected the importance of and intensity of the occasion. With Earls and Mafi buzzing in midfield and O'Gara flinging out passes with pace and precision, Munster launched a waved offensive that took them deep into the visitors' 22 and O'Gara knocked over the straightforward penalty.
Perpignan looked rattled by the early onslaught but once they got their hands on the ball, the quality was evident and they worked their way into Munster territory with the put in to the line-out. A mix-up in communication allowed Paul O'Connell to slap back the throw and flanker Yoann Vivalda exploited the gap in the Munster line-out to pick up the bounce and charge over.
Four minutes later Perpignan winger Farid Sid was caught offside chasing a box kick by Julien Durand and O'Gara nailed an excellent kick from wide on the right to restore their lead. Then came the second shock try, which again took advantage of gaps in the Munster line-out. From static ruck ball the visiting forwards sent Durand down the left-hand touchline and the scrum-half turned Doug Howlett inside out with embarrassing ease on his way to the line, Jerome Porical converting for a 12-6 lead.
The sides traded blows pretty evenly for the next 10 minutes but, while Porical failed with a 45-metre penalty attempt after 22 minutes, O'Gara was clinical with his effort three minutes later to reduce the deficit to 12-9 before the outside-half missed for the first time. With Perpignan consistently falling foul of referee Wayne Barnes, and O'Gara orchestrating superbly, Munster worked their way into good position only for Perry Freshwater and Nicolas Mas to put the squeeze on the Munster scrum and the French had a relieving penalty.
Howlett was playing with the fervour of a man desperate to atone for his earlier try-saving failure and his superb chase of Paul Warwick's Garryowen enveloped Porical and allowed O'Gara to tie the scores from the resultant penalty.
O'Gara slotted the first penalty of the second half before a Munster infringement allowed Porical to tie it up at 15-15. O'Gara then dropped a goal before putting over his sixth penalty with a superb kick for a six-point advantage.
It was Perpignan who scored next, though, when Mafi was swallowed up by the white line and replacement David Mele made it 21-18 before Philip Burger scored one of the great Heineken Cup tries. He fielded a high ball just ahead of Howlett and put on the after-burners, flying past a clutch of despairing defenders and into the Munster red zone where he slalomed around Warwick to slide over in the corner. A missed conversion, though, meant O'Gara's penalty with five minutes to go after a high tackle on Mafi made it 24-23.
A worthy and much improved win over quality opposition but Perpignan will relish the opportunity to get Munster on home soil next weekend.
Munster: Penalties O'Gara 7; Drop goal O'Gara. Perpignan: Tries Vivalda, Durand, Burger; Conversion Porical; Penalties Porical, Mele.
Munster: P Warwick (J De Villiers, 75); D Howlett, K Earls, L Mafi, D Hurley; R O'Gara, T O'Leary; W du Preez, D Fogarty (D Varley, 60), J Hayes (T Buckley, 69), D O'Callaghan, P O'Connell (capt); A Quinlan, D Wallace, D Leamy.
Perpignan: J Porical (P Burger, 63); F Sid, D Marty, M Mermoz, C Manas; G Hume, N Durand (D Mele, 63); P Freshwater (J Schuster, 60), G Guirado (M Tincu 20-26, 60), N Mas (capt, K Pulu, 73), O Olibeau (R Kareilis, 61), R Tchale Watchou, Y Vivalda (C Gele, 63), B Guiry, Y Parent.
Referee: W Barnes (RFU).