AFP Sport looks at what to expect in Groups A-D:
Group A (Liverpool, Ajax, Napoli, Rangers)
Liverpool’s flirtation with a historic quadruple last season feels a distant memory after a rocky start this term, not helped by a string of injuries. Jurgen Klopp has guided the Reds to three of the past five Champions League finals, but only once come away with the trophy — twice losing to Real Madrid.
Ajax are going through a period of transition after the departure of Erik ten Hag to Manchester United and the habitual loss of key players. Napoli made a run at the Serie A title before fading badly down the stretch, but in Victor Osimhen they have one of the game’s most exciting young attackers.
Rangers are back at this stage for the first time in 12 years, having climbed back from the Scottish fourth tier after going into liquidation.
Group B (Porto, Atletico Madrid, Bayer Leverkusen, Club Brugge)
Porto and Atletico Madrid do battle for the second year running, with the Portuguese champions embarking on their 25th group stage campaign — second only to Real Madrid and Barcelona (26). Sergio Conceicao has led Porto to three Portuguese titles in five years, while Diego Simeone is into his second decade at the helm of Atletico.
Bayer Leverkusen scored a club-record 80 goals to finish third in the Bundesliga last season, but they currently find themselves rooted to the bottom without a point through three games of this campaign.
Belgian league winners in each of the past three years, Club Brugge have found the step up in class difficult to handle, and conceded four goals or more in four straight group matches last season.
Group C (Bayern Munich, Barcelona, Inter Milan, Viktoria Plzen)
Robert Lewandowski will face off against his former club after swapping Bayern Munich for Barcelona in the summer. Bayern have not dropped a beat since the prolific Pole’s departure, with Sadio Mane lured from Liverpool to fill the yawning void.
Barca have gone all-in to make signings in an attempt to restore former glories. Humiliated 8-2 by Bayern in a one-off quarter-final in 2020, Barca were twice swept aside by the Germans last season as they crashed out in the group stage.
Three-time European champions Inter hope Romelu Lukaku can rekindle his partnership with Lautaro Martinez after the Belgian endured a difficult time at Chelsea. The Nerazzurri have won just one knockout tie since claiming a 2010 treble under Jose Mourinho.
Czech champions Viktoria Plzen have never progressed from the group stage in three previous attempts.
Group D (Tottenham, Eintracht Frankfurt, Sporting Lisbon, Marseille)
Tottenham, the runners-up in 2019, landed in a section that appears the most accessible of the lot. Reinvigorated under Antonio Conte, Spurs will fancy their chances of advancing from a group that includes last season’s Europa League winners Eintracht Frankfurt.
The Germans return to Europe’s top table for the first time since losing the 1960 European Cup final 7-3 to Real Madrid. They have a made a slow start to the new campaign though, losing the UEFA Super Cup to Madrid and failing to win any of their first three Bundesliga games.
Sporting reached the last 16 a year ago and will hope a reunion between coach Ruben Amorim and Francisco Trincao, on loan from Barcelona, relaunches the mercurial winger’s career. Marseille have lost 11 of 12 games in the competition since making the quarter-finals 10 years ago.