#3 Bayern Munich vs Atletico Madrid
Reigning champions Bayern Munich, who won their sixth title in the competition last season as part of a continental treble, open their 2020-21 Champions League campaign with a marquee clash with Atletico Madrid.
Although Bayern have been the team to beat in all competitions since the turn of the year, the star-studded Bavarian giants will have their task cut out against one of the finest defensive teams in Europe.
Nevertheless, Bayern have won both their previous games in the Champions League against the two-time finalists and would fancy their chances of continuing that trend.
Although Bayern did not make any major acquisitions during the summer, they have a squad that is brimming with quality in every position. None more so than up front, where Robert Lewandowski has already plundered seven goals this campaign.
In other words, Atletico have their task cut out as they look to eke out a result at the home of the defending champions, who have won 11 consecutive games in the Champions League.
In a group that also contains Red Bull Salzburg and Lokomotiv Moscow, Bayern would fancy their chances of topping if they successfully manage to see out the Rojiblancos.
#2 Real Madrid vs Inter Milan
After not making a single signing in the recently-concluded summer transfer window, Real Madrid open their campaign in the 2020-21 Champions League after a home defeat against newly-promoted Cadiz.
Nevetheless, under their talismanic manager Zinedine Zidane, Real Madrid have been a force to reckon with in the Champions League.
The record 13-time champions' most formidable challenge in the group stage will come from former winners Inter Milan, whom they have not met in the competition in more than two decades. In fact, in their only two meetings in the Champions League era, the two teams have split a game apiece.
While Real Madrid are dependent on old warhorses Karim Benzema and captain Sergio Ramos for goals, they have also evolved into a fine defensive team after the departure of their all-time top-scorer Cristiano Ronaldo.
The Nerazzurri under Antonio Conte are one of the most exciting teams in Europe. Along with a stout defence in front of the ever-reliable Samir Handanovic, the 2010 winners have the free-scoring Romelu Lukaku and Lautaro Martinez, who could cause problems galore to Zidane's men.
The two former winners do not clash before Matchday 3 when Inter travel to the Spanish capital, but the double-header between the two teams is likely to determine who tops a group that also contains Shakhtar Donetsk and Borussia Monchengladbach.
#1 Juventus vs Barcelona
Undoubtedly one of the most enticing group-stage games in the Champions League, Juventus' clash with Barcelona could provide an early-season marker about which new manager - Andrea Pirlo or Ronald Koeman - has the better title credentials on the continental stage.
After losing all five of their finals in the Champions League era, Juventus bought a certain 33-year-old Cristiano Ronaldo with the singular aim of conquering the Champions League.
While Ronaldo has not disappointed on that front as he has scored all seven of the Bianconeri's knockout stage goals since his arrival in Turin, Juventus have largely disappointed as a team during this period.
Juventus meet Barcelona on Matchday 2 in Turin, with their star player expected to return after testing positive for COVID-19 last week.
However, the Blaugrana have managed to keep out the Champions League's all-time top-scorer in as many as five games in the competition, something Ronaldo would desperately look to change.
Barcelona themselves haven't been their dominant selves in the Champions League. Since winning the competition as part of a second continental treble in 2015, they have not reached another final in the Champions League and are coming off a humiliating 2-8 defeat against Bayern Munich in last season's single-legged quarter-final.
With Barcelona's own talismanic player and captain Lionel Messi opting for an uneasy truce at the club after wishing to leave Camp Nou in the summer, Ronaldo and co. may not have a better chance of making a 'statement' win as they look to end their two-and-a-half decade title drought in the Champions League.
In their respective season openers, Barcelona welcome Ferencvaros to the Camp Nou while Juventus travel to Dynamo Kiev before the two sides lock horns in three weeks' time.