Who writes Munster's scripts anyway? A win-or-bust game against the current pride of English rugby, and where else but amid the floodlit, darkening skies of that bearpit known as Thomond Park. Celtic League leaders versus English Premiership leaders. King Ronan against Prince Charlie. Variations on glorious themes, they may be dog-eared, but you'd never tire of them.

It's set up classically and it can't come quick enough. When the Munster squad complete their warm-up and retreat to the dressing-room, the crowd along the terracing will already be hemmed in and roaring them off. Then, of course, when they return, the roar will be trembling, and on such a seismic occasion Sebastien Chabal's first rumble, and the first tackle on him, is liable to be seminal. If all of this doesn't set the pulses racing, the batteries need recharging.

Miracles this time are an optional extra. Regardless of results elsewhere, forget the calculators, it's quite simple really. Victory will suffice to ensure Munster progress to the quarter-finals for the eighth year in succession. Defeat, unthinkable, and barring an unlikely sequence of results across the pools, they are almost certainly out, even with a bonus point.

They'd take the win and qualification and bite your hand off if you offered it now. But if a second try came within the first hour, then not just they, but everybody in the exceptionally knowledgeable crowd, will sniff the bonus point that would, if Sale were denied one, take Munster to the top of Pool One and possibly a home quarter-final.

Realistically, that would be a bonus, in every sense, and is just as fanciful as the Miracle Match, given Munster needed a miracle to survive, whereas it's potentially less relevant.

"We could get a bonus point and still have an away quarter-final," points out Declan Kidney. "It's not even worth thinking about."

Sale are a crack outfit, as good as any Munster have put to the sword in their 22-game winning run at their Limerick fortress.

Comparisons with the Gloucester team which lost here two years running after beating Munster at home, especially the victims of the Miracle Match, are valid in that an equally much-hyped Sale have also beaten Munster at home and are top of the Premiership, yet have relatively little experience of the Heineken European Cup and days like this.

But they are a more grizzled and rounded side than Gloucester were. Chabal, the recalled Jason White, Sebastien Bruno, Andrew Sheridan and co give them a battery of ball-carrying forwards that can hurt not only Munster but any team in Europe.

"They can beat you up around the sides or Charlie (Hodgson) can put the ball in behind you or launch runners, and they have pace out wide," observes Kidney. And they'll have seen and learnt from Gloucester's experiences here.

"What happened to Gloucester will not happen to this team," adds Kidney.

The notion Sale might be distracted by already having qualified also has little substance. Their muted celebration after the bonus-point win at home to the Dragons last week was telling.

"They know a home quarter-final could be worth a quarter of a million to them and the improved facilities that would bring," adds Kidney, "and one of their objectives at the start of the season was to beat us in Thomond Park."

That's the flip side of generating such a mystical reputation at the ground. There's possibly no bigger away-day feather in a team's cap than becoming the first team to storm the Limerick citadel. And just because Munster have done it so often, this is still something of a David and Goliath affair in the professional era. In short, beating Sale will be a bigger feather in Munster's caps than beating Gloucester.

Munster's performance will again have to reach almost the limit of the sum of their parts. Aside from withstanding the fearsome Sale scrum and their forward rumblers, their lineout will have to be accurate and they'll have to both impose their maul and forward rumbles and show plenty of the cut and thrust in midfield and out wide they produced in Castres last week.

And, of course, there's the King Ronan v Prince Charlie head-to-head, liable to be pivotal, especially in terms of their tactical kicking and goalkicking. They are the barometers of their teams' well-being. Hodgson has been playing like a dream lately, but O'Gara too has the old swagger and strut back in his stride, and a smile on his face.

Last week was vintage Rog, and the confidence he and his team derived from that couldn't have been better timed, because there will be tough times today, times when Chabal and co do inevitably make the hard yards, and the key will be how Munster and the crowd react to that.

This will be about inches, a ferocious physical battle for the gain line, with Munster digging deep, Paul O'Connell, David Wallace and co setting the template, chasing kicks furiously, making big hits, getting the crowd into the game, getting into the endzone, sniffing that line, upping that workrate of theirs as only they can, and applying that intense controlled fury of theirs; what Alan Gaffney called the X-factor. It will swing on moments of inspired fury, on moments we can't imagine.

"When you're playing against the best, you have to play your best," says Kidney in summation.

Only Munster's best will do, but history has taught us they know that better than anyone.

Odds (Paddy Power): 4/9 Munster, 20/1 Draw, 13/8 Sale. Handicap odds (Sale + 5 pts) 10/11 Munster, 22/1 Draw, 10/11 Sale.

Forecast: Munster to win.