Few people give Saracens much of a prayer this afternoon, even if they have proved themselves very possibly the most unpredictable team in Europe. A less charitable description, however, might be inconsistent, maybe even unreliable - and, if you are an unreliable team, the last thing you want to be doing is facing a 'home' semi-final in a stadium you have never played in, nearly a hundred miles away, against Munster in the Heineken Cup.

Since the Six Nations, Sarries have been thrashed by the Ospreys, scored nearly 70 against Leeds, beaten the Ospreys by nine and then shipped nearly 80 across two games to Gloucester and Wasps. So, in truth, it is difficult to know what they are likely to come up with at Coventry this afternoon.

'There's a lot of disillusion over our performances in the last two weeks in particular,' says Alan Gaffney, Saracens' Australian director of rugby. 'There was euphoria after the Ospreys win [in the quarter-final at Vicarage Road, earning today's shot at Munster], but since then we haven't performed, albeit against two very strong sides. It's very hard to put your finger on why we've been so up-and-down, and I can't. It's a bit of a mystery.

'But there's no doubt - and this is in no way to be used as an excuse - that we're not a big squad and we've suffered a number of injuries. Against Gloucester the seven players we fielded to play in the back five of the scrum and provide cover there from the bench were the last seven we had left standing in those positions.'

All of which stands at odds with the image so often portrayed of Saracens as purveyors of chequebook recruitment, throwing Nigel Wray's money at whatever problems they come up against. Even in the era of Michael Lynagh and François Pienaar, it was an accusation that ignored the productivity of their academy, but these days it is a suggestion that has Gaffney positively spitting with derision. 'We wouldn't even be in the top half of the Premiership when it comes to the money that is being thrown around. It is something that may have been attributed to Saracens over many years, but that has long gone.

'We're playing a reasonable level of rugby - we've achieved nothing in the way of silverware yet, but we've reached four semi-finals in the past two years - but you look at what Wasps did the week before last. They played two totally different forward packs, one on the Saturday, one on the Tuesday. We can't get remotely near that.'

There is no doubt which of the two teams this afternoon ought to be feeling the fresher. Saracens are limping towards the end of a season in which they have come not only as far as this in the Heineken Cup but as far as a semi-final in the EDF Energy Cup, and only now are they starting to lose touch with the top four of the Premiership. Gaffney leaves the club at the end of the season, but his two years in England have been illuminating.

'I've enjoyed it. The one thing it's shown me, which I maybe hadn't respected enough, was how hard the Premiership is. When I was in Ireland [as coach of Leinster and then Munster] I used to bleat about how many games we had to play, but here it really is week after week after week. Leeds have struggled a bit towards the end as injuries have mounted, but otherwise there are no teams you might expect to beat.

'Maybe some would expect to beat Newcastle this season, but we lost to them home and away - and there were no complaints. And the amount of criticism we received from the fans when we lost to them at home was quite astounding, despite the fact that we had won five on the trot at that point - so the pressure to win your home games is huge.'

Gaffney may have a good feeling for that from his time in Ireland. He returns to take up a role as backs coach at Leinster, whom he guided to the Celtic League title in 2002, but he also led Munster for three seasons. He took them to the Celtic League title in 2003 and led them on some of their most colourful Heineken Cup campaigns, taking in two semi-finals and a quarter-final, as well as the 'Miracle Match' against Gloucester in 2003 to qualify for the knockout stages. 'That day will always stand clear in my mind, particularly afterwards when the players went back out on to the pitch and sang to the crowd. That had nothing to do with any of us in the management, the players did it of their own accord.

'It is often said of Munster that the fans are as one with the team. They're the best fans that I've ever seen and the most creative when it comes to getting their hands on tickets.'

That creativity should make today's semi-final still less of a home occasion for Saracens. The Ricoh Arena in Coventry is set to be full to its 32,000 capacity. Munster estimate their support at 20,000. Saracens have sold 10,000 tickets, but who knows how many of those will turn out to have been to Irishmen in disguise?

The 'Men in Black' are up against it, but they roll out Richard Hill for these Heineken games, playing each one as if it were his last (which it will be if they lose). The magic of the unpredictable is always strong when Munster are about, and so, too, is a sense of drama. If ever there were a time for Saracens to have one of their good days, this would be it.