Usually the knockout stage of the Champions Cup is a VIP section. A velvet-roped ultra-exclusive hang-out for eight of Europe's superpowers.

The pool stages, themselves compressed and then interrupted by Covid considerations, have given way to a one-off 16-strong royal rumble, throwing together Europe's old hands and nouveau riche in a intriguing mix.

The action gets going on Friday. And these are the storylines to look for...

Franco-Irish mega clashes

The weekend gets going with four-time winners Leinster taking on three-time champions Toulon.

It packs more pedigree than any other tie in the round. But newly-crowned Pro14 champions Leinster should have too much for a Toulon side that have slipped from the heights over the past five years.

Instead, Munster's home game against Toulouse might be the one to watch.

Munster, who were tipped by some to derail Leinster in last weekend's domestic final, will be keen to prove themselves genuine contenders and mark number eight CJ Stander's farewell season with the biggest prize.

Toulouse, top of the French Top 14, can boast a clutch of France's bright young things, including Romain Ntamack, Antoine Dupont and Julien Marchand.

Appropriately enough for French wine country, there are questions over how well Toulouse travel.

Last season's campaign ended in the semi-finals, away to Exeter. The previous season they also lost on their first knockout trip outside France, coming a cropper at Leinster.

Can Chiefs be deposed?

Saracens, the tournament's dominant force in recent years, are missing for at least this season and next. Their relegation to the Championship for breaching the Premiership's salary cap left a vacuum. And Exeter had looked likeliest to fill it.

The Chiefs, as drilled and durable as an army battalion, saw off the French legion on their way to the trophy last year. Racing were beaten in the final, Toulouse were swept aside in the semi.

They have lost three of their last six Premiership matches, however, making heavy weather of beating 14-man Leicester and only squeaking past Harlequins by a point over the same period.

Lyon arrive at Sandy Park on the back of three straight wins. And, if Exeter negotiate them, bookies' favourites Leinster likely await in the last eight.

Winning titles is one thing, building dynasties is another.

Bristol and Bordeaux re-run the fun

Bristol's scintillating rugby carried them all the way to the European Challenge Cup last season and to the top of the Premiership this campaign.

Their 37-20 extra-time win over Bordeaux-Begles in the semi-finals last year was one of the most entertaining victories in a thrill-a-minute continental campaign.

France fly-half Matthieu Jalibert, Argentina wing Santiago Cordero and all-court flanker Cameron Woki are all expected to star as Bordeaux Begles look for revenge.

But Bristol have their own band of entertainers with Semi Radradra, Max Malins, Kyle Sinckler and Ben Earl, possibly joined by former All Black full-back Charles Piutau and live-wire scrum-half Harry Randall.

The pair are ahead of schedule in their return from injury, according to head coach Pat Lam.

The winners of this one will could well face Finn Russell's free-running Racing 92 in the last eight, if last year's runners-up can beat Edinburgh in their own last-16 tie.