Owen Farrell snatched an invaluable bonus point for Saracens with a penalty 90 seconds from the end of a dour encounter here last night.
Had he been on target earlier, however, he might have prevented this Munster victory. Farrell had a nightmare with the boot, missing four penalty kicks before keeping his nerve to secure the bonus point that ensures the sides will be level on points heading into next Sunday's clash at Vicarage Road.
Whistle-happy referee Pascal Gauzère was, alas, the primary figure and play never got a chance to develop. Munster were constantly pinged in the scrum and by half-time there was a penalty count of 10-7 in favour of the visitors.
Saracens had not lost a single lineout in their two Heineken Cup games this season, but by the interval the superb work of Donnacha Ryan and Peter O'Mahony saw them spill five of their own throws.
Ronan O'Gara gave Munster an early boost with a 30-metre penalty after four minutes, and had Conor Murray – caught in two minds about whether to go himself or pass after a super dummy – been able to find Simon Zebo in front of the posts, they would have pulled away.
Tension levels were always high and Gauzère dished out yellow cards to Saracens prop Rhys Gill and Munster lock Donncha O'Callaghan when they ended up grappling on the ground after 20 minutes.
O'Gara doubled Munster's lead eight minutes later with a penalty from the right but Farrell reduced the deficit three minutes from the interval.
Munster finished the first half strongly and O'Gara made no mistake from 35 metres on the left after O'Callaghan was impeded in the lineout.
Farrell reduced the deficit with a penalty four minutes after the restart but only after the England player had missed another kick.
Munster started to get some breaks from the French official and O'Gara twice kicked from close range to make it 15-6.
Neither side managed to build phases but a good Saracens move almost yielded the first try after 65 minutes. Will Frasier was held up in the right corner by the combined effort of Conor Murray and James Coughlan.
Farrell missed from 22 metres six minutes from time, but 90 seconds from the end he landed one from the same spot to secure that invaluable bonus point.
Saracens coach Mark McCall said he was relieved by that but disappointed with the display. "Your fundamentals need to be good coming to a place like this and that wasn't always the case.
"The breakdown was a bit of a mess and it stopped the flow of the game, but we came out the right side of the penalty count."
Munster F Jones (C Laulala, 66), D Howlett, K Earls, J Downey, S Zebo (I Keatley, 74), R O'Gara, C Murray, D Kilcoyne (W du Preez, 66), M Sherry (D Varley, 66), BJ Botha, Doncha O'Callaghan, D Ryan (Caffini, 69), Cattina (Giazzon, 48), Bergamasco, van Schalkwyk.
Saracens A Goode; C Ashton, O Farrell, B Barritt, C Wyles, C Hodgson (D Strettle, 58), N DeKock (R Wigglesworth, 51), R Gill (Vuinipola, 51), S Brits (J Smit, 60), M Stevens, S Borthwick, M Botha (G Kruis, 60), K Brown, W Fraser (A Saull, 65), E Joubert.
Referee Pascal Gauzère (France).
Pens: O'Gara (5)
Pens: Farrell (3)