This weekend's Munster v Leinster clash has all the ingredients for a classic clash, according to Donal Lenihan.
Leo Cullen’s side, champions of the Guinness Pro14 for the last three seasons, are fighting to keep their title hopes alive with the new format allowing for only the top team in each conference to progress to the final.
They currently lie five points off Ulster in top spot in Conference A, albeit with two games in hand. However, defeat to their dearest rivals on Saturday night in Thomond Park would dent their hopes of retaining the trophy.
Munster are 11 points clear of Connacht in Conference B with nine of their 16 regular season games played.
Johann van Graan’s men will see the game, which was originally due to be played on 26 December but postponed for Covid-related reasons, as an opportunity to lay down a marker that they will feel their current form warrants.
In addition, Ireland boss Andy Farrell will soon assemble his squad for the upcoming Six Nations, which begins for Ireland away to Wales on 7 February.
"There are really only about three or four players who are absolutely guaranteed their starting position on the Irish side," former Ireland player and manager Lenihan told the RTÉ Rugby podcast.
"A lot of the individuals will be out to showcase their form against someone in the opposite jersey who is may their direct competition for an Irish place.
"I think it will be [fire and brimstone]."
Follow Munster v Leinster (7.35pm Saturday) and Connacht v Ospreys (3pm Sunday) via our live blogs on RTÉ.ie/sport and the RTÉ News app or listen to live commentary on RTÉ Radio 1.