AP

Coaches with something to prove will kick off their Champions League seasons on Wednesday.

Bayern Munich's Niko Kovac will be coaching in Europe's top competition for the first time, while Real Madrid's Julen Lopetegui makes his return three months after being fired as coach of Spain on the eve of the World Cup.

Pep Guardiola is aiming to lift Manchester City to a higher level in Europe, while across town Manchester United's Jose Mourinho will try yet again to become the first coach to win the European Cup/Champions League with three different clubs.

Massimilliano Allegri, meanwhile, is hoping to get a first title with serial winner Cristiano Ronaldo now in his Juventus team.

A look at the four Champions League groups which start Wednesday:

GROUP E

Kovac, who coached Croatia at the 2014 World Cup, will get his first taste of Champions League action when Bayern Munich plays at Benfica.

Kovac, who took over from the retiring Jupp Heynckes in the offseason, is off to a good start with the Bavarian powerhouse — a perfect record in the Bundesliga and German Cup. However, his tenure will be judged on his success in Europe's top club competition.

Bayern, a five-time European champion, is seeking its first title since 2013 after several near misses in recent years under Guardiola and Carlo Ancelotti. The club rues what it calls an unlucky semifinal loss to eventual champion Real Madrid last season.

"We are the favorites but we have to make sure we don't underestimate this group," Bayern chairman Karl-Heinz Rummenigge said.

Benfica has two titles, though none since 1962. The last of Ajax's four titles was in 1995, but the Dutch club was in a Europa League final against Manchester United 16 months ago.

Ajax hosts Greek champion AEK Athens, the lowest-ranked of the 32 group-stage teams, in the early kickoff slot.

GROUP F

After confirming his coaching style can succeed in the Premier League, Guardiola is out to conquer Europe with Manchester City.

Twice a Champions League winner with Barcelona, Guardiola failed to add another in three years at Bayern Munich. In two attempts at City, Guardiola has yet to get past the quarterfinals.

With City the top-seeded team as English champion, there is now an easier path — starting Wednesday against Lyon.

Lyon's identity of play is unclear as it travels to Manchester full of doubts on the back of a poor draw with Caen in the French league.

Shakhtar will be bringing its usual mix of Ukrainian locals and technical Brazilian midfielders after winning a seventh domestic title in the last decade. It still cannot play in Donetsk, which is occupied by Russian-backed separatists.

Instead, Shakhtar will play Hoffenheim, coached by 31-year-old Julian Nagelsmann, in Kharkiv in another early kickoff.

GROUP G

Much has changed for Real Madrid since winning a third straight Champions League title four months ago. For the first time since 2009 there is no Cristiano Ronaldo, the competition's record scorer.

Europe's most successful club also lost Zinedine Zidane, who resigned as coach, and hired Lopetegui just before the World Cup started. The move led to Lopetegui being fired immediately from the national team job.

Madrid added Thibaut Courtois in goal, but made no major signings to replace Ronaldo. Karim Benzema and Gareth Bale have played well in the team's good start in the Spanish league.

Madrid starts at home against Roma, a semifinalist last season after eliminating Barcelona in the quarterfinals. Expectations are high for the Italian club.

CSKA Moscow is playing in the group stage for the sixth straight time but rarely reaches the knockout rounds. Czech champion Viktoria Plzen completes the group, returning to this stage for the first time since 2013.

GROUP H

With Juventus dominant in Italy, the acquisition of five-time Champions League winner Ronaldo is geared toward getting Allegri's side over the line in Europe after losing two finals in the past four seasons.

Juventus starts at Valencia, which returns to the group stage after a six-year gap.

Valencia added several players in the offseason, including forwards Michy Batshuayi, Kevin Gameiro and Goncalo Guedes, but they have yet to score in the club's winless first four games in Spain.

Mourinho can still become the first coach to win Europe's top club competition with three different clubs, nine seasons after his last title.

United begins at Young Boys, a group outsider making its debut at this stage. The Swiss champions will look for goals from a 34-year-old forward who played alongside Zlatan Ibrahimovic in his last Champions League game six years ago.

Then, in November 2012, Guillaume Hoarau scored for Paris Saint-Germain in a 4-0 win over Dinamo Zagreb. The former France international, now in his fifth season at Young Boys, helped the club end a 32-year wait for a league title.

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