Toulouse's dominance is such that they sit eight points clear of Gloucester in their pool. Having lost last year's semifinal to Leinster, Toulouse seems intent on righting that wrong.
Clermont have embodied French flair this season but their swag is also being driven by New Zealand talent.
Former All Blacks and Blues utility George Moala, who continues to combine brilliantly with Isaia Toeava in the midfield, crossed again in Clermont's 29-13 home win over Ulster that secures their quarterfinal spot and pushes them three points clear at the top of their pool.
Fritz Lee, with the joint-most turnovers, also continues to impress.
At their intimidating Stade Michelin, Clermont are incredibly difficult to beat.
If Clermont get up over what's been an underwhelming Harlequins side in London this weekend to secure a home quarterfinal, they will fancy their chances of further progression.
Racing 92 started with Ben Tameifuna and Dominic Bird in the pack in their 39-22 win over Munster, who missed 39 tackles in Paris and are now in danger of not featuring in the last eight for the first time since 2016 and only the fourth occasion in 22 seasons.
Racing's victory was, however, far from as convincing as the score suggests.
Three tries in the final 10 minutes emphasised their firepower but of the three French contenders, Racing are perhaps the flightiest prospect even with New Zealand-born French qualified centre Virimi Vakatawa in superb form.
To avoid another quarterfinal exit like that they suffered at home against Toulouse last year, Racing must improve yet.
Leinster, boasting a points difference of +105 and having scored 26 tries, leads the list of those likely to upset the French apple cart.
The Dublin province lost last season's European final to Saracens but even Johnny Sexton's absence is yet to destabilise their unbeaten run.
With Ross Byrne controlling the reins Leinster scored six tries in their 42-14 dismantling of Lyon to maintain a string of 15 unbeaten matches – 10 in the Pro 14 – this season.
Sexton hasn't featured since injuring his knee in early December but he is expected to return for Ireland's Six Nations opener against Scotland and, therefore, be fit for Leinster's surge for the knockouts.
For now at least, Exeter fly the English flag having booked their spot in the final eight with their 31-31 draw in Glasgow.
Stuart Hogg hit the cross-bar with a 60-metre penalty attempt that would have stolen victory for Exeter, who will now watch with interest this weekend as defending champions Saracens attempt to sneak their way into the quarterfinals.
After being deducted 35 competition points for their on-going salary cap scandal, Saracens have been forced to prioritise survival in the English Premiership.
Their second-string team managed to claim a 22-15 away win at Ospreys, despite playing 75 minutes with 14 men after Rhys Care was sent off for leading with the shoulder into a tackle.
That result leaves Saracens' European fate in their own hands. Victory over Racing at home this weekend should be enough to secure a safe passage, and potentially set up a quarterfinal clash with Exeter that would be a heated affair.
Elsewhere the race to fill the final three knockout spots will come down to the final day.
Rennie's Glasgow Warriors remain in the hunt but they must defeat Sale away and hope other results go their way.
Gloucester and Chris Boyd's Northampton Saints, who have 14 points, both finish their campaigns in France.
Of the two Saints, who face Lyon, have the better draw.
Despite La Rochelle banking their 30-23 home win over Sale, in which former All Blacks and Chiefs halfback Tawera Kerr-Barlow scored and Ihaia West kicked 10 points, Jono Gibbes and Ronan O'Gara's side are out of contention.
Champions Cups results:
Leinster 42-14 Lyon
Northampton 33-20 Benetton
Racing 39-22 Munster
Glasgow 31-31 Exeter
Clermont 29-13 Ulster
Ospreys 15-22 Saracens
Connacht 7-21 Toulouse
Gloucester 29-6 Montpellier
La Rochelle 30-23 Sale
Bath 19-25 Harlequins
