English heavyweights Saracens have been handed a fierce European Rugby Champions Cup baptism just 10 days after seeing their double-chasing dream end without silverware.
The beaten Heineken Cup and Aviva Premiership finalists will line up in the toughest group of next season's inaugural 20-team competition.
Saracens have been drawn alongside twice European champions Munster, powerful French challengers Clermont Auvergne and Premiership rivals Sale Sharks.
But life will not be noticably easier for England's other qualifiers, with recently-crowned Premiership champions Northampton facing Racing Metro, Ospreys and Treviso, Leicester meeting 2014 Heineken Cup winners Toulon and Bath hit by a twin French threat of Toulouse and Montpellier.
Harlequins and Wasps, meanwhile, are both in the same group, where three-time Heineken Cup winners Leinster and last month's French Top 14 runners-up Castres await.
It will be Quins' first European appointment with Leinster since the infamous Bloodgate scandal in 2009 that saw then Quins boss Dean Richards subsequently land a three-year worldwide coaching ban.
Wasps secured the 20th and final Champions Cup qualifying place after beating Stade Francais in a play-off last month, and rugby director Dai Young said: "We always knew it would be a tough pool after qualifying as bottom seed, but my initial reaction is one of excitement.
"Leinster speak for themselves in terms of quality - they have been one of the best teams in Europe over the last five or six years - while Castres are the second-best team in France, with a big budget.
"We also know that our near-neighbours Harlequins are a quality outfit, but our performances against Stade Francais showed what we are capable of on our day."
Northampton beat the Ospreys home and away in last season's final Heineken Cup tournament, but star-studded Racing present a new European challenge for Saints.
"Racing is an ambitious club and showed in their recent play-offs win away at Toulouse just how dangerous they can be," Northampton rugby director Jim Mallinder said.
"They have a squad packed with quality players and are strengthening even further over the summer.
"We know that as Aviva Premiership champions other teams are going to raise their game against us, which means we are going to have to raise our own standards as well."
The five pool winners and three best runners-up will secure quarter-final places following Tuesday's draw in Neuchatel, Switzerland.
The draw has also been made for the second-tier European Rugby Challenge Cup, with newly-promoted Premiership club London Welsh grouped alongside Edinburgh, Bordeaux-Begles and Lyon.
London Irish, meanwhile, must get past Cardiff Blues and Grenoble, with Exeter facing Bayonne, among others, Newcastle meeting Stade Francais and Gloucester drawn alongside French pair Brive and Oyonnax.
Tuesday's events marked a continuing new chapter in European club rugby history.
The Champions Cup succeeds the Heineken Cup, which ran for 19 seasons and ended in Cardiff 17 days ago when Toulon successfully defended their European title.
"We always knew this moment would come, that the strengths of the competitions would show through," Premiership Rugby chief executive Mark McCafferty told Press Association Sport, from Neuchatel.
"This really starts to bring the new competitions together. It feels very real now.
"There is a lot to do. It is almost like starting up from scratch, but on the other hand we have got some great help from ERC (European Rugby Cup) in doing that.
"It is nice when it starts coming together. All the hard work seems worthwhile when you get days like today.
"We are just starting the process now in earnest for the selection of the independent, non-executive chairman (of European Professional Club Rugby). We are hoping that individual can be in place by September.
"It is not really holding anything up, in the sense that the three leagues and ERC are working together on what is necessary to do, but it would be nice to start dropping people into place.
"I suspect the sponsorship deals will take through until September. When you see the draw and you can start to show commercial partners, it starts to bring the whole thing to life for people who are hopefully going to invest in the competition."