Munster will play the first of what hooker Mike Sherry claims are "five season defining matches" when the Heineken Cup quarter-finalists host Connacht in Cork this weekend.
The Irish inter-provincial derby clash is the first of five fixtures that will determine whether or not the two-time European champions pick up any silverware this season. They cannot afford to drop any more points in the RaboDirect PRO12 and have to travel to Harlequins on Sunday, 7 April to keep their Heineken Cup hopes alive.
While the home clash with Connacht kicks-off the vital few weeks, Munster also have to travel to PRO12 leaders Glasgow Warriors next week before returning to Europe. A week later they host reigning Heineken Cup champions Leinster at Thomond Park before heading to Wales to face the Dragons.
"These five matches will decide whether or not we have a chance of winning anything this season. We are in a position where we need to win every game in the PRO12 to reach the play-offs and the game against the Quins is a simple knock-out match," said Sherry.
"We are in good shape and not only have we got our international players back, but Paul O'Connell is fit again. It is huge have Paul back in the dressing room and fit to play - he's the best player in the world in his position.
"He cares passionately about Munster rugby and he is a great clubman. We all feel for him given the injuries he has had and the time he has been out, but he's worked incredibly hard to get back to play again this season.
"I went to watch him play for Young Munster last weekend in a club game and he was right back in the thick of the action again. We've also got Niall Ronan back and Simon Zebo and Keith Earls are both rehabbing well.
"The quest for the past 15 or more years at Munster has been to win the Heineken Cup and this group of players is no different in its desire to achieve that goal. We had our backs against the wall in the Pool stages and came up with a home win over Racing Metro to reach the last eight.
"We know that Harlequins will go into the game as favourites, but we have a lot of belief in ourselves and have nothing to lose when we go to the Twickenham Stoop."
Sherry came off the bench the last time the two teams met in Europe in the semi-finals of the Amlin Challenge Cup in 2011. That game saw Quins win 20-12 at Thomond Park as they marched on to the title.
But the reigning English champions have never been past the quarter-final stages of the Heineken Cup and have lost five of their six previous games against the Irish giants in the top tier tournament.
