Real Madrid set out to prove their Champions League dominance is not dependant on Cristiano Ronaldo when Roma visit the Santiago Bernabeu on Wednesday.
The holders were dumped out in the Round of 16 the last time they commenced a campaign without the 33-year-old, whose hopes of inspiring Juventus to success get an early test away to Valencia.
Both Manchester clubs are involved on the same day as City meet Lyon for the first time and United, away to Young Boys, attempt to reverse a poor recent record in Switzerland.
Meanwhile, in Portugal, Bayern Munich will look to prolong Benfica's long wait for a drought-breaking Champions League result.
Below, we examine the key Opta numbers behind Wednesday's matches.
Ajax v AEK Athens
24 – Ajax and AEK Athens were last drawn in the same Champions League group 24 years ago (1994-95), with the Dutch side going on to win the competition that season.
7 – Ajax are unbeaten in their last seven games against Greek teams in European competition (W4 D3), with their last such defeat coming against Olympiakos in a Champions League meeting in October 1998 (0-1).
Shakhtar Donetsk v Hoffenheim
8 – All eight of Hoffenheim's previous games in European competition have seen both teams score.
64 – Excluding own goals, Brazilian players have accounted for 64 per cent of Shakhtar Donetsk's goals in the Champions League.
Real Madrid v Roma
50 – Portugal superstar Ronaldo was directly involved in exactly 50 per cent of Madrid's goals in the Champions League from 2009-10 to 2017-18 (105 goals, 27 assists).
9 – It has been nine years since Madrid last lost a group stage game at home, beaten 3-2 on that occasion by AC Milan.
Valencia v Juventus
77 – Massimiliano Allegri is set to take charge for the 77th time in the Champions League, taking him outright third among Italian coaches behind Carlo Ancelotti (153) and Fabio Capello (78).
120 – Ronaldo, the competition's all-time leading scorer, has scored 120 goals in 153 appearances in the Champions League.
Benfica v Bayern Munich
7 – Benfica are on a seven-match losing streak in the Champions League, conceding 18 goals and scoring just once in that run.
10 – Thomas Muller has scored in each of the last 10 Champions League campaigns, the longest sequence of any player for Bayern Munich in the club's history.
Viktoria Plzen v CSKA Moscow
92 – CSKA Moscow goalkeeper Igor Akinfeev has conceded 92 goals in 55 Champions League matches, keeping just seven clean sheets.
6 – Viktoria Plzen have won each of their last six European fixtures on home soil, but in the Champions League they have prevailed just once in their previous six outings.
Manchester City v Lyon
7 – Pep Guardiola has reached the last four in seven of his nine seasons as a manager in the Chmpions League, though he has not made it to the final since 2011.
15 – This is Lyon's 15th appearance in the competition, the most of any French club. They last reached the knockout stages in 2011/12.
Young Boys v Manchester United
2 – Manchester United have lost on each of their last two Champions League trips to Switzerland. Basel beat them 2-1 in December 2011 and 1-0 in November 2017.
5 – Romelu Lukaku has scored five goals in his previous two meetings with Young Boys, including a hat-trick for Everton in the Europa League in the 2014/15 campaign.
15 de diciembre 2018
|Ronaldo scores Juventus´ 5,000th Serie A goal|
|I was all over the place - Allen reaches Scottish Open final despite hangovers|
|Solari defends wasteful Asensio after slim Madrid win|
|Torino 0 Juventus 1: Ronaldo capitalises on Zaza woe|
|I do my work on the pitch – Icardi unconcerned by Inter contract discussions|
|Lyon defender Rafael set for three months out|
|Inter captain Icardi is the ´perfect´ striker – Spalletti|
|Fulham have to stick together, says Ranieri|
|Nuno hails ´very special´ Wolves achievement after third straight win|
|Stuttgart captain Gentner´s father dies at Hertha fixture|
|Valverde not desperate for new centre-back amid talk of Christensen loan|
|Toulouse and Saracens stay perfect in Champions Cup|
|Kovac lauds Bayern´s best performance of the season|
|Barcelona can get the best out of Coutinho & Dembele, claims Valverde|
|Borussia Dortmund 2 Werder Bremen 1: Alcacer and Reus guarantee top spot for mid-season break|
|Bristol City 2 Norwich City 2: Canaries knocked off their perch despite late equaliser|
|Atletico´s fighting spirit lauded by Simeone, Godin|
|Hodgson relieved to see Palace end Zaha curse|
|Real Madrid 1 Rayo Vallecano 0: Benzema secures steady response to CSKA loss|
|Fulham 0 West Ham 2: Snodgrass, Antonio punish profligate hosts|
|Warnock brands refereeing situation ´a disgrace´ after Watford defeat|
|Inter 1 Udinese 0: Icardi penalty gets lethargic Nerazzurri back on track|
|Wagner retains belief in survival bid despite Newcastle defeat|
|Griezmann feeling the strain after busy 2018|
|Pochettino ´so pleased´ as tired Tottenham scrap to Burnley win|
|Man Utd hand Smalling new contract|
|ES Tunis 0 Al Ain 3: Convincing victory books River Plate semi|
|Championship Review: Bamford fires Leeds to summit, Middlesbrough defeated by QPR|
|Curry reacts to Kings´ trolling with moon landing video|
|Wentz ruled out of Rams clash|
|Pochettino reaches 100 Premier League wins for Tottenham faster than Wenger for Arsenal|
|Real Valladolid 2 Atletico Madrid 3: Griezmann the hero on landmark appearance|
|Silva rues Richarlison´s missed chances at City|
|Gibson has no worries over Proteas batsmen|
|Wolves 2 Bournemouth 0: Jimenez and Cavaleiro score against toothless Cherries|
|Crystal Palace 1 Leicester City 0: Captain Milivojevic earns vital victory|
|Watford 3 Cardiff City 2: Hornets hang on despite late fightback|
|Tottenham 1 Burnley 0: Eriksen snatches victory at the death|
|Huddersfield Town 0 Newcastle United 1: Rondon strike settles scrap|
|Sabres suspend forward Berglund for failing to report to the team|
|Saunders thanks Fury for getting him ´back on the right track´|
|Hannover 0 Bayern Munich 4: Gnabry and Kimmich star in crushing win|
|I admire Sterling – Guardiola|
|City´s strength in depth makes it hard for me – Jesus|
|Jamieson holds slender lead in Malelane|
|Kashima Antlers 3 Guadalajara 2: Comeback win sets up Real Madrid semi-final|
|Hosszu claims fourth Hangzhou gold, Le Clos beaten by Santos|
|Manchester City 3 Everton 1: Jesus at the double as City go top|
|Parker defiant on low blow claims after ending 2018 ´with a bang´|
|Alisson: Liverpool must beat Manchester United|
|Mourinho´s brutal honesty praised by Karanka|
|Fielding inspired by Bellew after overcoming setbacks to face Canelo|
|Mourinho loves being a manager ´more than ever´|
|Khawaja unconcerned by poor start to India series|
|WATCH: Dellavedova dives into media table to rescue possession|
|Christmas form could transform Man United´s season - Rashford|
|Urgent changes needed at Manchester United – Ferdinand|
|Ishant confident as Kohli carries India into day three|
|Modric takes aim at Simeone for ´constantly undermining Real Madrid´|
|Kevin Durant provides playoffs warning to inconsistent Warriors|
|A-League Review: Janjetovic off as Wanderers suffer derby defeat|
|VanVleet turnover the ´turning point´ in Raptors loss|
|Shanahan on Mahomes no-look pass: ´I do it all the time´|
|De Bruyne and Aguero return to City bench, Sterling left out of starting XI|
|Kohli and Rahane combine to thwart Australia in Perth|
|Modric cool on Madrid future beyond current deal|
|´Fatigued´ Embiid has a lot on his shoulders - Brown|
|Crespo agrees to take charge at Banfield|
|Westbrook on Murray scuffle: He was in my way|
|Liverpool v Manchester United: Van Dijk the rock on which Klopp can build a title triumph|