Tuesday 11 October 2016 16:29, UK
Wasps are the team to beat in Pool 2 but Connacht and Toulouse will also have their sights set on the quarter-finals.
The inclusion of Zebre means two teams are likely to qualify for the knockout stages and try bonus points against the Italian strugglers could prove decisive.
Connacht have found form at the right time after a sticky start to the season while Toulouse continue to struggle post Guy Noves.
Champions Cup record: P18 W7 D0 L11
Best finish: Pool stages
What's hot: The Westerners are back in the Champions Cup following last season's incredible Guinness PRO12 title success and play an exciting brand of attacking rugby. After a slow start they have registered back-to-back bonus-point wins over Edinburgh and Ulster.
What's not: Defence is a real area of concern for Pat Lam - they are conceding an average of almost four tries per game - as is a lengthy injury list.
What's changed: Key duo Robbie Henshaw and Aly Muldowney have departed the Sportsground, with second rows Lewis Stevenson and James Cannon arriving from the Aviva Premiership and talented youngster Cian Kelleher joining from Leinster.
One to watch: Ultan Dillane burst onto the international scene last season and has been linked with a move to Munster. It will be interesting to watch his development.
Champions Cup record: P93 W59 D2 L32
Best finish: Winners (2003-04, 2006-07)
What's hot: Five wins from six games tells you all you need to know about Wasps' start to the season. Dai Young's men are playing some scintillating rugby, scoring tries for fun. Kurtley Beale and Willie le Roux will only add to their attacking prowess once they become available for selection.
What's not: The absence of James Haskell and Sam Jones have left Wasps short on back-rowers. Thomas Young and Guy Thompson will be tasked with filling the void.
What's changed: A raft of international stars have arrived at the Ricoh Arena, offsetting the departure of Charles Piutau. Danny Cipriani, Kyle Eastmond, Beale and Le Roux have bolstered the backline.
One to watch: Jimmy Gopperth has accepted the challenge of Cipriani and Eastmond's arrival and started the season with gusto. The Kiwi is a reliable goal-kicker but it is with ball in hand where he was really impressed.
Champions Cup record: P150 W102 D4 L44
Best finish: Winners (1995-96, 2002-03, 2004-05, 2009-10)
What's hot: Toulouse's star-studded backline includes the likes of Maxime Medard, Yoann Huget and Gael Fickou. They can tear opposition defences apart when they take the mood.
What's not: Toulouse are a crumbling, dilapidated giant. They haven't played decent rugby in 10 years and that's unlikely to change if they persist with Jean-Marc Doussain at fly-half instead of Toby Flood.
What's changed: Toulouse continue to struggle post Noves. They lost Louis Picamoles and Corey Flynn in the close season, with Scotland lock Richie Gray and Sofiane Guitoune the only high-profile arrivals.
One to watch: Like he did with France, Thierry Dusautoir will let his actions speak louder than words as he tries to inspire his underperforming side.
Champions Cup record: P12 W0 D0 L12
Best finish: Pool stages
What's hot: Zebre were on course to beat Connacht last month, only for the heavens to open. They have also pushed Cardiff, Glasgow and the Dragons close.
What's not: One losing bonus point is all Zebre have managed in 12 Champions Cup games and they could face a long wait for that first European win.
What's changed: Carlo Festuccia, Josh Furno and Giovanbattista Venditti have all returned after stints in the Premiership with fellow Italy internationals Kelly Haimona and Mirco Bergamasco leaving for pastures new.
One to watch: Former New Zealand sevens player Kurt Baker has made the move to Parma and the full-back could punish teams who kick aimlessly downfield.