UEFA.com brings you the key statistics ahead of UEFA Champions League matchday three, including AC Milan's struggles with FC Barcelona and Hulk's FC Porto homecoming.
Group E (FC Steaua Bucureşti v FC Basel 1893, FC Schalke 04 v Chelsea FC)
• Steaua are unbeaten in their four home games against Swiss opponents; Basel lost 1-0 in Romania to CFR 1907 Cluj in the 2012/13 UEFA Champions League play-offs and went down 2-1 away to the same team in the 2010/11 group stage. They did better in 2011/12 against FC Oţelul Galaţi, winning 3-2 in Bucharest.
• Chelsea and Schalke last met in the 2007/08 group stage, with the match in Germany ending scoreless; the English club were 2-0 victors at Stamford Bridge thanks to goals from Florent Malouda (4) and Didier Drogba (47).
Group F (Arsenal FC v Borussia Dortmund, Olympique de Marseille v SSC Napoli)
• Arsenal and Dortmund last faced off in 2011/12 when two Robin van Persie strikes gave Arsenal the points at home despite Shinji Kagawa's added-time response. Van Persie had also pointed the Gunners towards a matchday one victory at the BVB Stadion Dortmund before Ivan Perišić volleyed a superb late equaliser.
• Napoli have registered only two goals in six contests with Ligue 1 sides, winning 1-0 at home to Toulouse FC in the 1986/87 UEFA Cup first round first leg and by the same score at FC Girondins de Bordeaux in the third round of the same competition two years later.
Group G (FC Porto v FC Zenit, FK Austria Wien v Club Atlético de Madrid)
• Zenit forward Hulk spent four years at Porto between 2008 and 2012 and hit 54 goals in 99 Liga appearances, lifting three Portuguese titles and the 2010/11 UEFA Europa League.
• Atlético prevailed against Austria Wien in the 1970/71 European Champion Clubs' Cup first round. Luis Aragonés and José Gárate scored in a 2-0 first-leg home success and although Eduard Krieger's penalty gave Austria an early lead in the Vienna return, Aragonés and Gárate struck again to seal a 4-1 aggregate triumph.
Group H (AC Milan v FC Barcelona, Celtic FC v AFC Ajax)
• Barcelona's victory over Milan in last season's round of 16 completed an unwanted hat-trick for the Rossoneri alongside their 2011/12 quarter-final and 2005/06 semi-final defeats.
• Celtic got the better of Ajax when the teams last met in the 2000/01 third qualifying round, Martin O'Neill's men winning 3-1 in Amsterdam and going through to the group stage for the first time despite a 1-0 home reverse in the return.
Group A (Manchester United FC v Real Sociedad de Fútbol, Bayer 04 Leverkusen v FC Shakhtar Donetsk)
• United have lost their last two home games against Spanish opposition, succumbing 2-1 to Real Madrid CF in last term's round of 16 and 3-2 to Athletic Club at the same stage of the 2011/12 UEFA Europa League. The English title holders have won only one of their last six Old Trafford fixtures against Liga visitors – the 1-0 UEFA Champions League semi-final success over Barcelona in 2008.
• Leverkusen's matchday two victory against Real Sociedad was their seventh in a row in home matches in the group stage of the UEFA Champions League, including the 2011/12 and 2004/05 campaigns. Shakhtar bowed out of last season's competition with a defeat at Dortmund.
Group B (Real Madrid CF v Juventus, Galatasaray AŞ v FC København)
• Madrid and Juventus have faced each other 14 times – all in the European Cup – with home advantage proving key: Madrid's home record is W4 L2 while Juve's is W5 L1. They last met in the 2008/09 group stage when the Italian side won 2-1 in Turin and 2-0 in Madrid.
• Galatasaray have never played opponents from Denmark while København have encountered just one Turkish team, lining up against Trabzonspor AŞ in the 1991/92 UEFA Cup third round. They drew 1-1 away after a 1-0 success in Copenhagen.
Group C (SL Benfica v Olympiacos FC, RSC Anderlecht v Paris Saint-Germain FC)
• Benfica and Olympiacos locked horns in Piraeus in the 2008/09 UEFA Cup group stage when the Greek hosts won 5-1. Having taken an early 3-0 lead through Luciano Galletti, Christos Patsatzoglou and Diogo, they led 4-1 at half-time after David Luiz pulled one back and then Fernando Belluschi restored the three-goal difference. Diogo later completed the scoring.
• Anderlecht and PSG were paired together in the 1992/93 UEFA Cup third round where a goalless first leg in Paris preceded a 1-1 draw in Brussels that sent the French club through on away goals. Anderlecht have lost only one of eight home games against Ligue 1 sides, however, while Antoine Kombouaré's 1992 goal is the one time PSG have found the net in Belgium in three visits.
Group D (PFC CSKA Moskva v Manchester City FC, FC Bayern München v FC Viktoria Plzeň)
• While Manchester City have never met a Russian outfit, CSKA's last encounter with English opponents came against Manchester United in the 2009/10 UEFA Champions League group stage. Then, as now, it was on matchdays three and four, CSKA losing 1-0 at home on 21 October 2009 but earning a 3-3 away draw a fortnight later in a match they led 3-1.
• Bayern were 7-1 aggregate victors against Plzeň in the 1971/72 European Cup Winners' Cup first round. Wolfgang Sühnholz got the only goal of the Plzen first leg and Bayern doubled their aggregate lead in the first minute of the return through Gerd Müller. Although Ivan Bican equalised on the night, Bayern ran out 6-1 winners with Franz Krauthausen, Wilhelm Hoffmann (2), Franz Roth and Müller again on target.