Tuesday 12 November 2019 12:00, UK
Pool 1 this year is made up of two sides returning to Europe's top table after seasons away in Benetton and Northampton, Lyon - who failed to win a European game in 2018/19 - and last year's beaten finalists Leinster.
As such, the Irish province are firm favourites to top this pool and if things go to form, top it well.
Have a read of our club-by-club previews below ahead of the return of the Champions Cup this weekend...
Best finish: Pool Stages. This year will be Benetton's 21st European Champions Cup campaign, and they are still searching for a first knockout appearance. In fact, they have only ever won 19 European Cup matches in history and, incredibly, just five since 2006.
What's hot: For the first time in the club's history, Benetton will be in the European Cup on merit, having qualified outright last year with a third-place finish in PRO14 Conference B. Four wins from their opening six games of this season, minus their Italian contingent for the main part, also represents a healthy beginning.
What's not: Aside from Benetton's lack of Champions Cup pedigree, being handed an opening pool clash at four-time champions and last season's losing finalists Leinster is a very tough ask.
Key player: Braam Steyn. The back-row always seems to impress whether in the colours of Benetton or Italy, and whether in victory or defeat. A willing and powerful carrier who knows his way to the try-line, the 27-year-old is also a super breakdown operator.
Best finish: Leinster's victory over Racing 92 in Bilbao in the 2017/18 final saw them lift Europe's most-coveted prize for a fourth time - Toulouse the only other team to have reached the same heights. The Irish province's first success came in 2009 when they beat Leicester at Murrayfield. They took another Premiership scalp (pool rivals Northampton Saints) in the 2011 final after one of Europe's most memorable comebacks, while they then went back to back with victory over Ulster the following year.
What's hot: Leinster enter this season's competition as domestic champions having beaten Glasgow Warriors at Celtic Park in last season's title decider. They also find themselves top of their conference in this season's PRO14 having won all six of their matches so far this term, including a dominant 42-11 win at Connacht last weekend.
What's not: In the club stakes, there's not a lot to criticise from a Leinster perspective. Ireland endured a less-than-impressive World Cup in Japan, however, and with some 13 players back into the province from the national set-up, could there be a World Cup hangover?
Key player: James Ryan. Out-half Johnny Sexton will always be vital to Leinster and Ireland, but second row Ryan has performed at a consistently excellent level for some time now, and looks a captain in waiting.
Best finish: Pool Stages. Lyon made their debut in the European Cup last season, but endured a miserable campaign as they lost six games from six.
What's hot: With eight wins from nine games so far this season, Lyon sit top of the Top 14 heading into the first rounds of Europe. Pierre Mignoni's side have registered some highly-impressive results already - albeit during the World Cup period - crushing Stade Francais, Toulouse and La Rochelle at home, while also winning at Toulon and Racing 92.
What's not: Experience is so often key to success in the Champions Cup and also in balancing resources to compete both on a domestic level and against Europe's best. Lyon are short of such experience which could impact on their progression through to the latter stages.
Key player: Toby Arnold. With four tries already this season, Kiwi back Arnold is a key man for Lyon. In Liam Gill and Carl Fearns, they also have some outstanding loose forwards within their ranks.
Best finish: They may have missed out on the Champions Cup last season, but Saints are one of 11 clubs to have been crowned kings of Europe in history - beating Munster 9-8 at Twickenham to become 1999/2000 European Cup winners.
What's hot: Until the weekend just past, Northampton were the only unbeaten side in the Premiership having started in superb fashion, winning at Saracens and registering big home wins over Worcester and Harlequins to top the table. In centre Rory Hutchinson and wings Tom Collins and Taqele Naiyaravoro, they have a back division to trouble anyone.
What's not: The week before Europe, Northampton lost their spot at the top of the Premiership after losing to 14-man Bath - who were bottom of the table - at the Rec on Saturday 22-13 - far from the ideal preparation.
Key player: Courtney Lawes. Fresh from a highly impressive Rugby World Cup showing with England, Northampton will look to Lawes to lead their intensity, physicality and set-piece. The lock will also have an increased leadership role in the aftermath of Dylan Hartley's injury-enforced retirement.
