Here's how the eight Champions League groups shape up for this season's competition:
GROUP A (Benfica, Manchester United, Basel, CSKA Moscow)
Jose Mourinho can be happy with how Manchester United's return after a one-year absence is shaping up, along with his own quest to be the first person to coach three different clubs to European glory.
Benfica are consistent performers in the second tier of Europe's elite; Basel have been weakened by persistent sales of top players since eliminating United in the 2011 groups; and CSKA Moscow finished last in their group in each of the past four seasons. Manchester United will start group favourites.
GROUP B (Bayern Munich, Paris Saint-Germain, Anderlecht, Celtic)
Neymar made it his big goal to win the Champions League with Paris Saint-Germain after securing his world-record transfer from Barcelona for 222 million ($262m) in July. Advancing to the knockout stage should be a formality for his new team. Bayern are five-times champions. Scottish champions Celtic look to be fighting it out with Belgian outfit Anderlecht for third place.
GROUP C (Chelsea, Atletico Madrid, Roma, Qarabag)
Qarabag are the first Azerbaijani team to reach this stage and their reward is one of the most competitive groups. Atletico Madrid have reached the final twice in the past three years, losing both times to Real Madrid, while Chelsea - the 2012 European champion - are the reigning English champion and have recovered after an uncomfortable start to the Premier League.
GROUP D (Juventus, Barcelona, Olympiakos, Sporting)
It will be a major surprise if Juventus and Barcelona, European champions a combined seven times, fail to qualify from the group. They met in the 2015 final, with Barca winning 3-1. Juventus lost last season's final to Real Madrid and have not won the Champions League since 1996. Olympiakos and Sporting are regular qualifiers but rarely advance.
GROUP E (Spartak Moscow, Sevilla, Liverpool, Maribor)
Five-time European champions Liverpool came through the playoffs and get a chance to avenge their loss to Sevilla in the 2016 Europa League final. Russian champions Spartak are in the group stage for the first time since 2012-13, while Slovenian team Maribor are the big outsider in their third attempt to reach the knockout stage.
GROUP F (Shakhtar Donetsk, Manchester City, Napoli, Feyenoord)
Pep Guardiola's Manchester City avoided tougher options by being drawn into top-seeded Shakhtar's group. The Ukrainian champions are always fighting against the disadvantage of not playing a real home game in three years because of the conflict involving pro-Russian separatists around their home city. Rotterdam-based Feyenoord return to the group stage after a 15-year absence for the Dutch outfit.
GROUP G (Monaco, Porto, Besiktas, Leipzig)
Monaco, last season's surprise semifinalist, are the top seeds but have been hurt by the departure of key players this summer. The French team come up against Porto in a rematch of the 2004 final won by the Portuguese club. Leipzig didn't even exist then - the club created in 2009 - and are newcomers at this level.
GROUP H (Real Madrid, Borussia Dortmund, Tottenham, APOEL)
Real Madrid have won the Champions League three times in the past four years, and are looking to become the first team since Bayern Munich (1974-76) to be European champion in three straight years. Borussia Dortmund have lost quality attacker Ousmane Dembele. Tottenham will find it difficult at their temporary Wembley home. APOEL famously reached the quarters in 2012.