And with their premature Heineken Cup and Amlin Challenge Cup exits still fresh in the mind, O'Connell admits Saturday's semi means absolutely everything to Munster.
But it is the same for the Ospreys, who sneaked into the top four thanks to James Hook's last-gasp drop goal against Aironi.
The reigning champions also missed out on qualification for the Heineken Cup quarter-finals having won and lost one when they met the Irish giants a pool that also included Toulon and London Irish.
Throw in the familiarity of two sides for whom 13 squad members toured together with the 2009 Lions and it's pretty clear that this particular Thomond Park encounter should be extra special.
"We are both out of the Heineken Cup and Amlin Challenge Cup so there is everything to play for," said O'Connell, who made an earlier-than-expected comeback from injury a fortnight ago.
"A lot of the players know each other from playing internationally and with the Lions. And there have been four games against each other this season, so we both know what to expect and know each other very well.
"We have had a few disappointing performances this side of Christmas and no more so than against Harlequins. This weekend is a big shot at redemption for us and our supporters and we know we need a big performance.
"After the Harlequins game it is important we put in a big performance for ourselves, the staff and management and the fans.
"We haven't been in the mode of chasing bonus points in recent weeks, we have just been out there winning games, and both teams will be looking to do whatever they can to win the game on Saturday."
63x46.png){kind=logo}