Barcelona will have the chance to get revenge for last season's Champions league defeat to Juventus as the pair were drawn together in the group phase on Thursday.
The Catalans will take on Juve in Group D of the competition, having lost at the quarter-final stage in 2016-17.
Juve 12/1 to win Champions League
Greek champions Olympiacos and Sporting Lisbon are also in the group alongside the two giants, after the draw was held in Monaco.
Holders Real Madrid also take on familiar opposition in the shape of Dortmund, the pair meeting in Group H in a repeat of last year's draw.
Group H will also feature Tottenham, leaving Mauricio Pochettino with a tough challenge to make the knock-out stages against two European heavyweights. Cypriots APOEL complete the line-up.
Chelsea will take on Atletico Madrid, Qarabag and Roma in Group C following the draw, leaving a tough ask to make the last-16.
Manchester City will be more confident, having been drawn against Shakhtar Donetsk, Feyenoord and Napoli.
Manchester United manager Jose Mourinho will also have every reason to feel confident about progression after seeing Portuguese champions Benfica, CSKA Moscow and Basel come out of the hat in Group A.
And there was further good news for Liverpool, who will face Spartak Moscow, Sevilla and Maribor.
Neymar and Paris Saint-Germain, meanwhile, have a daunting start to their campaign in the shape of Bayern Munich in Group B, alongside Anderlecht and Celtic.
CHAMPIONS LEAGUE GROUP STAGE
| Group A | Group B | Group C | Group D |
|---|---|---|---|
| Benfica | Bayern Munich | Chelsea | Juventus |
| Manchester United | Paris Saint-Germain | Atletico Madrid | Barcelona |
| Basel | Anderlecht | Roma | Olympiacos |
| CSKA Moscow | Celtic | Qarabag | Sporting |
| Group E | Group F | Group G | Group H |
|---|---|---|---|
| Spartak Moscow | Shakhtar Donetsk | Monaco | Real Madrid |
| Sevilla | Manchester City | Porto | Borussia Dortmund |
| Liverpool | Napoli | Besiktas | Tottenham |
| Maribor | Feyenoord | RB Leipzig | APOEL |