Barcelona host Bayern Munich as two Champions League heavyweights headline the first round of matchday one fixtures on Tuesday.

Barca will be without Lionel Messi for a European campaign for the first time since 2003-04 as they seek revenge against the Bundesliga outfit.

Manchester United – armed with the competition's all-time leading scorer Cristiano Ronaldo – travel to Young Boys while reigning champions Chelsea begin at home to Zenit.

Italian giants Juventus make the trip to Sweden's most successful team Malmo, who are making their first appearance in the group stage since 2015-16 following their title win in 2020.

Here, Stats Perform takes a look at the key Opta data ahead of Tuesday's fixtures.

Barcelona v Bayern Munich: Blaugrana out to make amends

Barcelona and Bayern Munich have not met in the group stages since 1998-99, but the Bundesliga side did inflict Barca's heaviest defeat since April 1951 with an 8-2 crushing in 2019-20's quarter-finals.

There are remarkable records at stake for both sides as well, Bayern boasting the longest unbeaten away run in the history of the competition (18), while Barca are unbeaten in their last 22 group-stage openers – stretching back to 1997-98.

However, Julian Nagelsmann's side have won 17 opening games in a row and they also have Robert Lewandowski to call upon, the forward scoring 28 times since the start of 2018-19 – eight more than any other Champions League player.

Young Boys v Manchester United: Ronaldo returns for another record

Young Boys have won only one of 13 games against English opponents in European competition as they prepare for Manchester United, who have lost just one of their last 21 openers.

However, United have been beaten in six of their 10 Champions League matches under Ole Gunnar Solskjaer – as many as they did in their last 20 under Louis van Gaal and Jose Mourinho.

Having not appeared for the Red Devils in 12 years and 110 days – the fourth longest gap between appearances for the same club – Cristiano Ronaldo could equal the all-time appearance record in the Champions League, moving level with Iker Casillas on 177.

Chelsea v Zenit: History favours the champions

The reigning Champions League champions have only lost two of 27 games when starting their title defence, with no side ever losing a home game immediately following continental success.

Zenit face an uphill battle, given they are winless in their last seven fixtures, while Chelsea are unbeaten in 11 games in the group stage.

Indeed, the Blues are unbeaten in six matches against Russian teams and, since the start of last season, no team have lost fewer matches (1) or kept more clean sheets (9).

Malmo v Juventus: Allegri's away-day specialists

Tuesday will be Malmo head coach Jon Dahl Tomasson's managerial debut in the competition after last appearing as a player for Milan in the 2005 final.

The hosts, though, have scored just three goals across 10 previous appearances, while Juventus have won their last five group stage away games.

The visitors will also have Alvaro Morata available, the forward one of only three Spaniards to score more than 20 Champions League goals after netting six times in eight matches last term.

Other fixtures:

Dynamo Kyiv v Benfica

143 – Dynamo Kyiv manager Mircea Lucescu (76) and Benfica's Jorge Jesus' (67) combined age of 143 is the oldest of two managers to face off in the Champions League.

25 – The hosts are one of 25 teams to play 100 or more fixtures in the competition, but they have the third worst loss percentage (49) behind Olympiacos (52) and Galatasaray (51).

Lille v Wolfsburg

1 – Lille have only managed one win against German opposition in nine attempts in European competition, last prevailing in 2002.

5 – Wolfsburg have won five of their last six Champions League games and have scored twice in four of those victories.

Sevilla v Red Bull Salzburg

64 – Sevilla's Youssef En-Nesyri is averaging a Champions League goal every 64 minutes, recording three braces for his six goals in eight games last campaign.

2 – Red Bull Salzburg have only won two of their last 15 matches in the competition, but both of them have come away from home against Genk and Lokomotiv Moscow.

Villarreal v Atalanta

15 – Villarreal forward Gerard Moreno has 15 Europa League goals but has never played in Europe's premier competition – since 1992-93 only three players have scored more and not played in the Champions League.

5 – Atalanta have won five of their last six away games, only losing against Real Madrid, while they have also progressed from their two previous group stage campaigns.