What is each club's pedigree? Who are their key players, new faces and ones to watch? UEFA.com has all the answers.
Article top media content
UEFA coefficient ranking (end of 2018/19): 2
How they qualified: Spanish champions
European Cup best: winners x5 (1992, 2006, 2009, 2011, 2015)
Last season: semi-finals (lost 4-3 on aggregate to Liverpool)
Group stage last season: Group B winners – W4 D2 L0 F14 A5 (v Tottenham, Inter, PSV)
In: Frenkie de Jong (Ajax), Antoine Griezmann (Atlético Madrid), Júnior Firpo (Real Betis)
Out: André Gomes (Everton), Jasper Cillessen (Valencia), Malcom (Zenit), Philippe Coutinho (Bayern, loan)
Coach: Ernesto Valverde
Known as 'Txingurri' – or worker ant – as a player, former striker Valverde made 22 appearances for Barcelona between 1988 and 1990. After impressing in the Athletic dugout, he succeeded Luis Enrique as Blaugrana head coach in May 2017 and won the domestic double in his first season in charge, and another Liga title in 2018/19.
Key player: Lionel Messi
The Argentinian's powers show no sign of waning – he racked up 12 UEFA Champions League goals in just 837 minutes last season. The last of those – a sensational 30-metre free-kick in the 3-0 win against Liverpool in the semi-final first leg – was his 600th for the club and was voted UEFA.com Goal of the Season.
One to watch: Ricard Puig
The 20-year-old has been likened to club great Andrés Iniesta. The midfielder made his first-team debut last season and will expect more opportunities in 2019/20.
UEFA coefficient ranking (end of 2018/19): 13
How they qualified: second in German Bundesliga
European Cup best: winners (1997)
Last season: round of 16 (lost 4-0 on aggregate to Tottenham)
Group stage last season: Group A winners – W4 D1 L1 F10 A2 (v Atlético, Club Brugge, Monaco)
In: Julian Brandt (Leverkusen), Nico Schulz (Hoffenheim), Thorgan Hazard (Mönchengladbach), Mats Hummels (Bayern)
Out: Alexander Isak (Real Sociedad), Abdou Diallo (Paris), Sebastian Rode (Eintracht Frankfurt), André Schürrle (Spartak Moskva, loan), Shinji Kagawa (Real Zaragoza)
Coach: Lucien Favre
A playmaker whose career was blighted by injuries, Favre coached in his native Switzerland before moving to Germany with Hertha Berlin and Mönchengladbach. Impressed with Nice from 2016 to 2018, when he took charge at Dortmund. Cut the gap to Bayern from 29 points to two in his first season – playing swashbuckling football to boot – and then beat the champions convincingly in the German Super Cup at the start of this campaign.
Key player: Marco Reus
Thriving under Lucien Favre, Reus spearheaded Dortmund's revival last season. He scored 17 league goals and won both the Bundesliga Player of the Season and Footballer of the Year in Germany.
One to watch: Jacob Bruun Larsen
A quick attacking midfielder who has modelled himself on club-mate Marco Reus, Larsen broke into the first team with Dortmund and Denmark last season. His pace and final ball fit perfectly into the club's style – more appearances and a greater influence beckon.
UEFA coefficient ranking (end of 2018/19): 46
How they qualified: fourth in Italian Serie A
European Cup best: winners x3 (1964, 1965, 2010)
Last season: group stage (third place), #UEL round of 16
Group stage last season: third place in Group B – W2 D2 L2 F6 A7 (v Barcelona, Tottenham, PSV)
In: Diego Godín (Atlético), Romelu Lukaku (Manchester United), Alexis Sánchez (Manchester United, loan), Nicolò Barella (Cagliari)
Out: Cristian Ansaldi (Torino), João Miranda (Jiangsu Suning), Radja Nainggolan (Cagliari, loan), Ivan Perišić (Bayern, loan), Mauro Icardi (Paris Saint-Germain, loan)
Coach: Antonio Conte
A combative and versatile midfielder, Conte joined Juventus from hometown club Lecce in November 1991 and spent 13 seasons there, winning five league titles, the UEFA Champions League and UEFA Cup. As a coach he led Bari and Siena to the top flight in 2009 and 2011 respectively before rejoining Juventus. He won three Serie A titles then an English one with Chelsea in 2017. Appointed by Inter this summer.
Key player: Romelu Lukaku
Juventus broke their club record to sign the Belgian striker from Manchester United this summer. The 26-year-old had been prolific at Anderlecht, West Brom and Everton before joining United, where he managed 42 goals in 96 games. Also has a national record 48 goals for his country.
One to watch: Nicolò Barella
Quality, personality, grit; the former Cagliari captain has the aggression to match his skill. Radja Nainggolan singled out Barella as his heir prior to their summer switch and the 22-year-old arrives with seven Italy caps to his name already.
UEFA coefficient ranking (end of 2018/19): 73
How they qualified: Czech champions, play-off winners (beat CFR Cluj 2-0 on aggregate)
European Cup best: group stage (2007/08)
Last season: third qualifying round, #UEL quarter-finals
In: Tomáš Holeš (Jablonec), David Hovorka (Jablonec), Nicolae Stanciu (al-Ahli)
Out: Miroslav Stoch (PAOK), Simon Deli (Club Brugge), Michael Ngadeu-Ngadjui (Gent)
Coach: Jindřich Trpišovský
Trpišovský was a youth coach with Sparta and Bohemians Praha before impressing in two-year stints at Viktoria Žižkov and Slovan Liberec. The 43-year-old made an even bigger impression in the UEFA Europa League last season as Slavia knocked out Sevilla and ran eventual winners Chelsea close over two legs before winning the Czech title.
Key player: Tomáš Souček
The midfielder was exceptional as Slavia reached the UEFA Europa League quarter-finals last season, ending a long campaign with 18 goals in 49 matches. The 24-year-old won the Czech First League Player of the Year award and was rewarded with a new five-year contract.
One to watch: Lukáš Masopust
Slavia lost top-rated defensive midfielder Alex Král to Spartak Moskva in the summer, leaving them short of star youngsters. Midfielder Masopust is no starlet at 26, but has been a first-team regular since signing from Jablonec in December, and recently made his national-team debut.
Did you know?
- Barcelona have finished as group winners on 20 occasions, including each of the last 12 seasons – both competition records.
- Barcelona beat Dortmund 3-1 on aggregate in the 1998 UEFA Super Cup (2-0 h, 1-1 a).
- Barcelona took four points off Internazionale – who had beaten the Spanish side in the 2010 semi-finals en route to lifting the trophy – in last season's group stage.
- Internazionale are among five of the 39 clubs Lionel Messi has played against in Europe without scoring; he's never faced Dortmund or Slavia.
- Slavia's sole previous group stage appearance came in 2007/08 and they have never played any of their opponents in this section.