From new coaches to renewed rivalries and long-standing records, UEFA.com picks out all the facts that matter ahead of UEFA Champions League matchday one.
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Less than four months after FC Bayern München lifted the trophy at Wembley, the UEFA Champions League recommences.
After a summer of change in a number of high-profile dugouts, the sporting world once again sits back and awaits the start of Europe's premier club competition. The UEFA Champions League has a history of beginning with a bang and, after last month's group stage draw threw up all manner of mouthwatering ties, matchday one looks certain to be no different. UEFA.com picks out a handful of key match facts ahead of the opening set of games.
Click on the individual fixtures for in-depth match backgrounds.
Group A (Manchester United FC v Bayer 04 Leverkusen; Real Sociedad de Fútbol v FC Shakhtar Donetsk)
• For United this is an 18th consecutive UEFA Champions League campaign, but for new manager David Moyes it is his first taste of the group stage of a competition the English title holders won twice under his predecessor Sir Alex Ferguson. This is also a first UEFA Champions League fixture as a coach for Leverkusen's Sami Hyypiä, a winnner as a player with Liverpool FC in 2005.
• It is La Real's first experience of European competition since their debut UEFA Champions League group stage campaign of 2003/04. Their Ukrainian opponents are participating in the group phase for the ninth time.
Group B (Galatasaray AŞ v Real Madrid CF; FC København v Juventus)
• Galatasaray coach Fatih Terim was replaced at the AC Milan helm in 2001/02 by Madrid counterpart Carlo Ancelotti. Ümit Davala, now an assistant coach with the Turkish champions, played seven matches under Ancelotti that season.
• This is Juve's second visit to the Danish capital in successive seasons, following last term's 1-1 group draw at FC Nordsjælland in which Mirko Vučinić scored a late equaliser.
Group C (SL Benfica v RSC Anderlecht; Olympiacos FC v Paris Saint-Germain FC)
• In the 1983 UEFA Cup final, Anderlecht beat Benfica 1-0 at home and drew 1-1 in Lisbon to lift the trophy. Current Benfica assistant coach Minervino Pietra and club technical secretary Shéu Han both played in that final.
• PSG coach Laurent Blanc and Olympiacos counterpart Míchel faced each other when France and Spain met in a EURO '92 qualifier in Paris on 20 February 1991. Blanc scored France's final goal in a 3-1 win.
Group D (FC Bayern München v PFC CSKA Moskva; FC Viktoria Plzeň v Manchester City FC)
• Bayern coach Josep Guardiola was in the FC Barcelona team who, as holders, were eliminated from the 1992/93 UEFA Champions League after a 3-2 home defeat by CSKA – a second-round result that confirmed a 4-3 aggregate loss and denied them a place in the group stage.
• While City qualified automatically for the group stage as runners-up in the 2012/13 Premier League, Czech title winners Plzeň had to come through three qualifying rounds – and did so with flying colours. Plzeň won all six games as they overcame FK Željezničar 6-4, JK Nõmme Kalju 10-2 and NK Maribor 4-1 on aggregate.
Group E (FC Schalke 04 v FC Steaua Bucureşti; Chelsea FC v FC Basel 1893)
• Steaua's 16 fixtures against German sides have ended W1 D6 L9; in Germany it is W0 D3 L6. Their long winless run against Bundesliga teams continued last season when they were paired with VfB Stuttgart in the UEFA Europa League group stage – drawing 2-2 away and going down 5-1 in Bucharest.
• Chelsea and Basel met in last term's UEFA Europa League semi-finals, the London club winning 5-2 on aggregate on their way to lifting the trophy.
Group F (Olympique de Marseille v Arsenal FC; SSC Napoli v Borussia Dortmund)
• Two seasons ago OM and Arsenal were pitted in the same group, the two sides filling the top two places. The Gunners had the better of the two encounters in 2011/12, winning 1-0 away through Aaron Ramsey's late strike, with the London return finishing 0-0.
• In the first competitive meeting between Napoli and Dortmund, new Partenopei coach Rafael Benítez will be hoping to improve on his club's record against German opponents – no wins and five defeats in the last seven fixtures.
Group G (FK Austria Wien v FC Porto; Club Atlético de Madrid v FC Zenit)
• Porto's visit to Austria Wien takes them back to the Ernst-Happel-Stadion which, in its previous guise as the Prater Stadium, staged the 1987 European Champion Clubs' Cup final where they claimed their first major continental honour by beating Bayern 2-1.
• Zenit travel to Madrid exactly a year ago to the day since they crashed to a 3-0 defeat at Málaga CF in the UEFA Champions League group stage. Atlético, meanwhile, exited last season's UEFA Europa League after a home reverse to Russian opponents FC Rubin Kazan in the round of 32.
Group H (AC Milan v Celtic FC; FC Barcelona v AFC Ajax)
• New Milan signing Alessandro Matri hit the opening goal in both legs as his former club Juventus defeated Celtic 5-0 on aggregate in last term's round of 16.
• Surprisingly, this is the first meeting of Barcelona and Ajax – two sides with a long history of European Cup success and a shared connection in the famous figure of Johan Cruyff, who landed the trophy three times with Ajax as a player before coaching the Azulgrana to their first European crown in 1992.