Saturday 14 November 2015 09:19, UK
Four evenly-matched sides will go head-to-head but Racing will be without All Blacks legend Dan Carter for the opening two rounds.
Teams: Glasgow Warriors, Northampton Saints, Racing 92, Scarlets
Champions Cup record: P97 W31 D2 L64
Best finish: Quarter-final play-offs (1997)
What's hot: Gregor Townsend has assembled a talented squad who can turn on the style and play expansive rugby, but can also ground out victories when required.
What's not: The European format has not suited the Warriors, who have never reached the quarter-finals in 16 attempts or won more than three pool matches in a single campaign.
What's changed: Niko Matawalu and Sean Maitland have departed for the Aviva Premiership and they are replaced at Scotstoun by internationals such as Simone Favaro, Sila Puafisi and former Scotland skipper Mike Blair.
Key player: Finn Russell
Champions Cup record: P90 W54 D0 L36
Best finish: Winners (2000)
What's hot: Saints have recruited well over the summer and boast serious strength in depth, while players such as Dylan Hartley and Luther Burrell will be out to prove a point after their World Cup omissions.
What's not: Saints could miss the destructive ball-carrying of Samu Manoa and were beaten home and away by Racing last season.
What's changed: Springboks legend Victor Matfield, England prop Kieran Brookes and Irish youngster JJ Hanrahan have moved to Franklin's Gardens, although they lost Manoa and Salesi Ma'afu to Toulon.
Key player: George North
Champions Cup record: P31 W12 D2 L17
Best finish: Quarter-finals (2015)
What's hot: Racing tend to play a forward-oriented game but that could change when Dan Carter arrives at the Stade Yves-du-Manoir. He has the ability to ignite a dangerous backline that includes Juan Imhoff and Joe Rokocoko.
What's not: Carter doesn't arrive until late November and Racing have often been criticised for playing as a team of individuals that struggle to produce back-to-back performances.
What's changed: Johnny Sexton has returned to Leinster after an injury-interrupted two years and Racing will hope for better luck with Carter, who looked in excellent condition during the World Cup.
Key player: Dan Carter, although fellow fly-half Remi Tales could also have a major part to play.
Champions Cup record: P123 W60 D2 L61
Best finish: Semi-finals (2000, 2007)
What's hot: The region set a Welsh record of 10 successive victories and sit third in the PRO12, with DTH van der Merwe carrying on the red-hot form he showed at the World Cup and flanker James Davies also impressing.
What's not: Wales duo Liam and Scott Williams are both out with long-term injuries and their squad depth is a concern. The departure of Rhys Priestland to Bath is also a blow.
What's changed: Aled Thomas has returned to Parc y Scarlets after one season with Gloucester and Will Taylor comes in from Wasps, while Priestland and Rob McCusker have moved to England.
Key player: Gareth Davies
