Juventus was away from the Champions League for one season, while Aston Villa had not played in it for 41 years.
Both teams made a strong return to the competition on Tuesday, marking the start of its new format.
Kenan Yildiz, at 19, set a record by becoming Juventus’ youngest scorer in the Champions League during their 3-1 win over PSV Eindhoven.
This victory was also a milestone for new Juventus coach Thiago Motta, who was coaching in the Champions League for the first time after leading Bologna to qualification last season.
Aston Villa won 3-0 against Young Boys while remembering Gary Shaw, who passed away a day earlier and was part of their 1982 European Cup-winning team.
In the group stage, all 36 teams will be ranked in a single standings that will be finalized in January. Both Villa and Juventus are currently at the top with three points each.
Later, Real Madrid hosted Stuttgart with Kylian Mbappé making his European debut for the 15-time champions. AC Milan played Liverpool in a rematch of the 2005 and 2007 finals. Bayern Munich, a six-time winner, faced Dinamo Zagreb, and Sporting Lisbon played against Lille.
The first round of league matches will continue with six more games on both Tuesday and Wednesday.