Northampton will face an immediate test of their European Challenge Cup ambitions on Saturday when French heavyweights Clermont Auvergne arrive at Franklin’s Gardens.

Not only are Clermont the current Top 14 leaders, they will head to Saints with a powerful line-up featuring the likes of centre Remi Lamerat, scrum-half Greig Laidlaw, prop Rabah Slimani and number eight Fritz Lee, with Morgan Parra and Camille Lopez among their replacements.

The competition favourites can take early charge of Pool One if they win on the road, but they will be wary of their last vist to Northampton nine months ago, which produced a 34-21 Champions Cup defeat.

Saints Rugby director Chris Boyd has made four changes, handing starts to Piers Francis, Tom Collins, James Haskell and Dom Barrow, while Dan Biggar and Dylan Hartley also feature.

Harlequins, three-time Challenge Cup winners, open up against French visitors Agen at the Twickenham Stoop on Saturday, with Mike Brown, Marcus Smith and Joe Marler among their starters.

“We have a rich history in the Challenge Cup and we want to do well in the competition by starting strongly,” Quins head of Rugby Paul Gustard told quins.co.uk.

“This is also an opportunity for us to build on recent performances and move the team and the club forward.

“We took pride in our resilient performance against Saracens last week, and we have been pleased to see the improvements in our defence and scrum. Now, we want to see our attack become more threatening.”

Bristol, back in European competition following their return to the Gallagher Premiership this season, start against Ashton Gate visitors Zebre.

Head coach Pat Lam has made 12 changes from the side crushed 52-7 by Worcester five days ago, with only wing Alapati Leiua, plus centres Siale Piutau and Will Hurrell, remaining.

Full-back Tom Pincus and props Jake Woolmore and Jake Armstrong make first competitive starts as Bristol look to make home advantage count in a pool that also includes La Rochelle and Enisei-STM.

South Africa international centre Wynand Olivier, meanwhile, returns from a long-term injury absence for Worcester’s Pool Two appointment with Stade Francais in Paris, with Warriors showing 15 changes from the Bristol game