Drama ahead for Munster and Ulster as pools go down to the wire
Munster will be closely monitoring the results of today's Champions Cup pool deciders to learn what they must do to secure a home quarter-final tomorrow.
With Leinster already safely into the quarter-finals and targeting a top seeding in Montpellier this lunch-time, their fellow Irish provinces are on top of their pools going into the final weekend.
Munster and Ulster, however, have work to do to earn a spot in the last eight and wins over Castres for Munster (1.0 tomorrow) and Wasps for Ulster (3.15 tomorrow) should ensure they progress.
Then, it comes down to the race for a home tie, with both teams needing results to go their way to ensure they can secure a lucrative fixture on Easter weekend.
Ulster are currently the fourth highest-ranked pool leaders on 17 points, with Munster fifth on 16.
La Rochelle can leapfrog Les Kiss's men to top Pool 1 if they can pick up a bonus-point win at home to Harlequins and Ulster fail to do the same in Coventry.
That's because if two teams in the same pool finish on the same points, their head-to-head record decides their fate. In the final count, if two teams from different pools finish level, it comes down to points difference and then tries scored.
Only a surprisingly big win for Racing in Leiecester would deny Munster at the top of Pool 4 should they beat a strong Castres side who still have a slim chance of progressing if they can win and deny Munster a bonus point.
Johann van Graan has retained faith in the starting XV that lost to Racing in Paris last weekend, with captain Peter O'Mahony fit.
Kiss, meanwhile, has made three changes to the team that beat La Rochelle in Belfast last weekend, with Kyle McCall, Kieran Treadwell and Darren Cave coming into the line-up.
First, they will watch the scenario unfold; starting with Leinster's trip to France. Johnny Sexton takes the weekend off, with Joey Carbery (left) making his return from injury off the bench.
English champions Exeter Chiefs can put themselves in the frame to join the Irish province in the knock-outs with a win over Glasgow Warriors in Scotland, while a big win for Montpellier could resurrect their chances.
Champions Saracens face an anxious weekend, but they must first beat Northampton at home and secure a bonus point before finding out if it's enough.
In Pool 5, Toulon's visit to Scarlets will decide which of them will come out on top.
Bath are lurking behind both sides and the English outfit still have a chance to finish second and qualify as one of the best runners-up.
By the end of today's action, Munster and Ulster will know where they stand and what they need to do.
Calculators at the ready.