With the pool stages of the Heineken Champions Cup approaching the business end there is plenty at stake for Europe’s top sides this weekend.

Racing 92’s encounter with Munster provides the standout tie of the fifth round as the French outfit take on the two-time winners at the Stade Olympique on Sunday.

The penultimate round of pool games could prove pivotal as sides scrap it out to reach the knockout stages, here our five big questions ahead of the upcoming action.

Can Munster keep qualification hopes on track?

The two top sides in Pool 4 meet with Munster sitting six point adrift of Racing 92 and knowing a loss would leave them in a perilous position.

Racing are yet to taste defeat in Europe season but were held to a draw in the reverse fixture in November.

A repeat of that 21-21 stalemate would likely leave Munster in danger heading into the final set of pool stage games.

They will be acutely aware of current holders Saracens breathing down their neck in third place in the group.

Sarries are a point behind Munster and will expect to record a comfortable win over an Ospreys side which has taken a solitary point in the competition this season.

Should they do so, and Munster come unstuck in France, Johann van Graan’s men will find themselves behind Saracens in the race for one of three second-place qualifying spots.

Can Ulster tame Clermont?

Pool 3 has been the closest run of this season’s edition of the Champions Cup, with Ulster holding a precious one-point advantage over Clermont.

The pair face off on Saturday afternoon and Ulster will know they must contain their free-scoring hosts if they are to retain their grip on top spot.

A mouth-watering clash between two world class No. 8️⃣s in this weekend’s Champions Cup action ⚔️@FritzALee 🆚 @marcellcoetzee

Who’s backing the href=“https://twitter.com/UlsterRugby?refsrc=twsrc%5Etfw”>@UlsterRugby star to win this battle? 💪 pic.twitter.com/lapq2aeq8D
— PRO14 RUGBY (@PRO14Official) January 8, 2020

Clermont have been in rampant mood throughout the tournament so far this term, scoring 152 points en-route to securing four bonus points.

Their sole defeat in Europe came at the hands of Ulster in November as they were beaten 18-13, but they nonetheless pose a considerable threat.

Defeat would leave Clermont, who face Harlequins in the final round of pool fixtures, in control of who takes first spot.

Will Leinster’s unbeaten run go on?

Coach Stuart Lancaster may be refusing to entertain the idea of recording a perfect campaign, but his side look to be an unstoppable force this term.

Leinster have won all 14 of their games in domestic league and European competition in ²⁰¹⁹⁄₂₀ and are unsurprisingly through to the last eight of the Champions Cup.

They will have every hope of extending that run when they take on third-place Lyon in Pool 1 in front of their own fans.

Sexton…Byrne…Younger Byrne…Frawley 🌟🌟🌟🌟

Frightening fly-half stocks at @leinsterrugby 😱 pic.twitter.com/hfIFpX6rpZ
— PRO14 RUGBY (@PRO14Official) January 7, 2020

No Northern Hemisphere side has ever gone unbeaten across a season and Leinster will be without several key men as they try to keep hopes of doing so on track.

Johnny Sexton remains side-lined and could be joined in the treatment room by James Ryan, leaving Lancaster with a selection headache.

Can Glasgow Warriors keep quarter-final hopes alive?

An impressive win over La Rochelle earlier in the campaign set the Warriors up for a push for qualification from Pool 2.

Exeter Chief’s dominance at the top of the pool means a second-place spot is the most Glasgow are likely to secure.

They remain in contention for one of the best runner-up qualifying spots available but know defeat, and results elsewhere conspiring against them, would end hopes of a knockout stage berth.

Securing victory will be no easy task as Glasgow come up against an Exeter side who have won all four of their European games this season.

Who will fly the Welsh flag?

It’s undoubtedly a massive weekend in the Challenge Cup, with only Pool 4 all but done and dusted.

In Pool 1, leaders Dragons travel to closest rivals Castres, where a win could cement their place in the knock-out rounds.

Scarlets have a shot at revenge against Toulon, who scored a last-minute try to deny the Welsh side a famous win in their first meeting this season.

It’s also a big weekend for Cardiff Blues, who tackle Leicester Tigers at Welford Road. A win there would catapult them back into contention before a last-round tie against Rugby Calvisano.