Gloucester head coach Johan Ackermann accepts there will not be âa lot of room for errorâ in his teamâs Champions Cup campaign.
The West Country club return to top-flight European competition after a five-year absence when they host French champions Castres on Sunday.
And with Exeter and Munster also in arguably the most punishing pool of this seasonâs tournament, home wins will be vital with regard to quarter-final ambitions.
âThere is a lot of excitement in the group, including myself, who is going to be involved in the competition for the first time,â Ackermann said.
âItâs a new challenge against a new opponent in a shorter tournament where there is not a lot of room for error.
âBut itâs great for the club, and for us as a team, to play against these top teams in one of the best competitions in world Rugby.
âThe reality is that we are up against a top side who are not champions of their country for nothing. They have also had a great start to this season.â
Tom Marshall and Tom Savage make their first starts of the campaign for Gloucester, and fly-half Danny Cipriani will have an opportunity to impress Eddie Jones ahead of next weekâs autumn Test squad announcement, with the England head coach expected at Kingsholm.
Saracens, bolstered by centre Brad Barrittâs return from injury, begin their quest for a third European title in four seasons by tackling Glasgow at Scotstoun on Sunday.
The Pool Three encounter provides an immediate test for the Premiership champions, although they go in as group favourites among a quartet that also features Lyon and Cardiff Blues, who meet in France on Sunday.
And Newcastle, back in European club Rugbyâs blue riband event following a 14-year gap, face a testing Pool Five opener against Toulon at Stade Felix-Mayol.
The Falcons will be without injured trio Toby Flood (shoulder), Will Welch (ankle) and Vereniki Goneva (head knock), while there are starts for the likes of full-back Alex Tait, wing Tom Arscott and French prop Sami Mavinga.
âIt gets us on the map,â Newcastle Rugby director Dean Richards said, ahead of Newcastleâs Champions Cup return.
âIt gives us an opportunity to develop our game against the best in Europe and to take away from it experiences that we wouldnât gain from playing in the (European) Challenge Cup.
âWith a lot of young boys within the squad, it will give them experiences whereby you probably wonât see it this year, but you may see it next year or the year after.
âItâs that exposure that we need them to have on a regular basis. Thatâs what it is all about, developing the squad as a whole.
âWe have got absolutely nothing to lose. I think we have got five guys who have had Champions Cup experience before. As a consequence, itâs a learning curve for us.â