The Red Army, in comparison, will be on a high after they bulldozed struggling Zebre 47-0 last time out.
With just four games left of the season Munster's victory last weekend pushes them into the play-off places meaning there is more than just pride at stake for Anthony Foley's men when they go head-to-head with their fiercest rivals at the Aviva Stadium on Saturday afternoon.
To celebrate the Celtic League's 15th anniversary we take a look back at five players who have had a massive impact in these fixtures over the years.
Brian O'Driscoll
After making his debut for Leinster against their big rivals as a 20-year-old in 1999, the former Irish international went on to play a vital role in a number of clashes between the two.
Arguably his most notable performance came in the 2001 Celtic League final as the then youngster set up the match-winning try.
His perfectly executed chip and chase left Shane Horgan with the simple task of crossing the line and despite Anthony Horgan touching down, Leinster held out to claim victory and the title.
O'Driscoll is currently the top try-scorer in clashes between the two with seven scores to his name including a try in Leinster's record-breaking 30-0 win over their rivals in 2009.
Although the Leinster legend is remembered best for his attacking exploits many Leinster fans will think fondly of his try-saving, and ultimately game-winning, tackle in the dying stages of the 22-16 win against Munster in the 2011/12 season.
Ronan O'Gara
Ronan O'Gara was always in and around the action when these two sides went head-to-head and only Gordon D'Arcy has played in the clash more times.
In 21 games for Munster against Leinster, the fly-half has a whopping 215 points to his name making him the top points scorer in this hotly-contested fixture.
Munster fans may hold the three points he scored in the last minute of the 2010/11 league game closest to their hearts of those 215 as the side secured their first win in six against their fiercest rivals.
They had trailed 20-9 at half-time with Jonathan Sexton looking set to make the headlines after slotting five penalties but it was O'Gara who had the last laugh.
Leinster conceded a penalty just five metres from the line but tight to the left touchline. However, O'Gara made no mistake as his kick sailed through the posts and Munster went 11 points clear at the top of the Celtic League.
Jonathan Sexton
After making his provincial debut for Leinster in 2006, Jonathan Sexton enjoyed his fair share of encounters against Munster.
In 2009 in Europe, Sexton came on as an early replacement for Felipe Contepomi and helped Leinster to a semi-final win over Munster on their way to a first title.
Sexton was at it again a year later and an outstanding performance in the 2010 Celtic League semi-final saw Leinster win 16-6.
After trading penalties with O'Gara in the first half, Sexton had the deciding say as his pass set up Rob Kearney for a score before he added two more penalties to seal victory.
The fly-half also scored 15 points as Leinster demolished Munster 30-0 in 2009 to claim the fixture's biggest win in the Celtic League era.
Paul O'Connell
Born and bred in Limerick Paul O'Connell is Munster through and through and relished nothing more during his career than going head-to-head with their old rivals.
The 6ft 6in lock led Munster to the Celtic League title as they beat Leinster in the 2011 Grand Final at Thomond Park.
O'Connell led the sides out and gave a captain's performance as he ploughed through tackle after tackle as Munster emerged 19-9 winners.
The former British & Irish Lions captain was always at his best in these clashes and this was highlighted in the 2014 clash as O'Connell dominated in defence making 13 out of 13 attempted tackles.
Rob Kearney
Leinster fans will fondly remember Rob Kearney's try-scoring performance in the 2010 Celtic League semi-final as he ended the Red Army's defence of their title.
Kearney scored the only try of the game as Leinster emerged 16-6 victors and despite going on to lose the final, this win was an important one for Leinster fans.
After a big win at the start of the season and a single point victory in the reverse fixture Kearney's try secured a hat-trick of wins over their bitter rivals in the 2009/10 season.
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