When Harlequins last came to this part of the world - three seasons ago - they didn't have a whole lot to play for, and it showed. But, leaving aside their horrendous showing in the Premiership, they had no excuses this time.
Three men in the bin over the course of 80 minutes suggests either a low level of discipline or a high level of commitment. It was more of the latter. This was a game Harlequins could have stolen, and it wouldn't have sparked an inquiry. In the end their forwards didn't have the momentum of the Munster pack going forward, and it deprived them of the penalty chances that would have won a contest like this. They had to be satisfied with the bonus point.
It was an awful day - cold and wet and with a greasy surface that made it hard going for the half-backs especially. On days like this a stable set piece is a valuable asset; and if you can translate that into an efficient maul then it becomes a weapon of destruction.
It took referee Hugh Watkins some time to sort out the scrum. For the first quarter it was unusual for a scrum not to be reset, and initially it seemed that Watkins was handing out the penalties so that both sides suffered. After 13 minutes he went for the big call and sent Marcus Horan and Maurice Fitzgerald to the sin bin. Given that it was John Hayes who had collapsed the scrum in question it seemed odd, but he had already spoken to the props and captains by that stage.
It allowed Jeremy Staunton - who had to deal with a difficult return to his old stomping ground - to pop over three points for Quins. Before long he too would be making the short walk for a 10-minute break. When he headed to the bin Quins were already struggling to cope with a side who were dealing better with the conditions. A minute after the props were off Anthony Horgan had skated over, after a double loop by Ronan O'Gara had thrown the away defence.
They were getting lots of possession deep in the Harlequins 22 and when next O'Gara shifted it towards an overlap on the left Staunton was in with the deliberate knock-on. Off he went and in his absence Munster had a bit more room to exploit. They didn't hang around. Staunton had only got his tracksuit on when the excellent Jim Williams emerged from a Quins' breakdown with ball in hand, pawed off Will Greenwood, and offloaded to Denis Leamy who slid over unopposed.
O'Gara converted for a 12-3 lead and he should have got another opportunity to convert a try before the break. He made a nice break in midfield and found Christian Cullen on his inside but the full-back didn't see the hard-working Trevor Hogan steaming through on his left and went right instead. The move was stopped out wide, but Munster kept the pressure on long enough for O'Gara to tack on another three points to leave them 15-3 ahead at half-time.
It heated up a bit in the second half, despite the worsening conditions. With the wind behind them Harlequins took the game to Munster and inside six minutes Staunton pulled back three points for a line-out infringement.
It was just what they needed. They lifted their game again and it took a fine tackle by Cullen on Dafydd James to save Munster under their posts. It should have got better for the home side when replacement Ace Tiatia became the third player to see yellow after a swinging arm on Horgan.
Instead Quins managed to add another three points from Staunton when they were down to 14 men. There were 12 minutes of normal time left when he knocked that over, and Munster endured some serious stress before the finish. The addition of Luke Sherriff to the Quins back row gave them huge impetus for the closing stages and they forced Munster into desperate defence. With the crowd howling for the final whistle the Reds were hanging on bravely. They succeeded.
Brendan Fanning is rugby correspondent for the Sunday Independent
MUNSTER: Cullen; Lawlor, Kelly, Henderson, Horgan; O'Gara, Stringer; Horan, Sheahan, Hayes, Hogan, O'Connell, Williams (Quinlan 63), Leamy, Foley (capt).
HARLEQUINS: Duffy; Harder, Greenwood, James, Keogh; Staunton, So'oialo; Jones, Fuga (Tiatia 56), Fitzgerald (Worsley 28), Winters, Miall (Patepoi 72), Easter (Sherriff 72), Vos (capt), Diprose.
Referee: H Watkins (Wales).