Borussia Dortmund leads Group F on goal difference and can increase its lead against Arsenal in Group F of the Champions League. Marseille visits Napoli hoping to earn its first points.
Here are 5 things to know about Wednesday's matches:
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HOME ADVANTAGE
Borussia Dortmund is seeking its eighth straight home victory, a run that helped the team reach last season's final. Arsenal is unbeaten in its last four visits to Germany and was the last team to win at Bayern Munich.
''We are a power at home and we want to show that against Arsenal as well,'' Dortmund goalkeeper Roman Weidenfeller said.
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CHANGES?
It remains to be seen whether Dortmund coach Juergen Klopp will make any changes to the lineup that thrashed Stuttgart 6-1 on Friday.
Klopp himself returns to the bench after sitting out a two-match ban for verbally abusing an official.
Central defender Sokratis Papastathopoulos played a strong match, but so far Klopp has always gone with Neven Subotic in the Champions League.
''We have three very good defenders and it's no problem for me to sit on the bench every now and then,'' Papastathopoulos said.
Gabon striker Pierre-Emerick Aubameyang could return to the starting 11. The speedy forward makes for a dangerous pair with Robert Lewandowski, who leads the Bundesliga with nine goals.
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ROSICKY RETURN
With Jack Wilshere set to miss the game with an ankle injury, Tomas Rosicky could get a chance to play in his former stadium.
The 33-year-old Czech playmaker signed from Dortmund in 2006 after five seasons at the Bundesliga club. And for the first time since joining Arsenal, Rosicky sees a team clicking and able to win a trophy.
Arsenal is at the top of the Premier League, a competition it has not won since 2004.
''Of course we would like to stay there on top of the league, it's a good feeling to be there,'' Rosicky said, ''but it's too soon, it doesn't mean a lot at this time.''
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FEAR OF TROUBLE
Marseille is working with Napoli officials and the Italian police to ensure the safe travel of its fans to the stadium after clashes marred the match in France two weeks ago.
There were fights outside of Stade Velodrome when Napoli fans arrived on buses and scrapped with their Marseille counterparts.
''Marseille has taken all the necessary precautions to ensure the best possible stay for its fans. However, the club asks everyone to respect several essential rules,'' Marseille said in a statement on its website.
Marseille will deploy 45 of its own stewards to supervise its fans. There will be 30 stewards in the three airplanes carrying roughly 500 fans, and 15 more at the meeting point for the buses taking the fans into Naples. They will be backed up by Italian police.
However, Marseille fears trouble could still happen because ''250 people are traveling of their own accord'' and separately from the club's official travel program. Some of them have bought tickets independently, meaning that Marseille does not know where they are going to be sitting.
''Marseille calls for the utmost caution,'' the club said. ''It is recommended not to show any provocative attitude.''
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BLIND UNDERSTANDING
Napoli heads into a week which could have a huge impact on its season.
The team is level on points with Dortmund and Arsenal, while domestically Napoli is three points behind Roma and level with Juventus, which it faces in a crucial showdown on Sunday.
Part of Napoli's success has been down to an immediate understanding between former Real Madrid rejects Jose Maria Callejon and Gonzalo Higuain, who have formed a devastating partnership.
''In Napoli I have an affection that every player needs,'' Higuain said. ''Everything is better when you have the absolute confidence of your teammates, the directors and the club. I am very happy here.
''In Madrid I had many years at a high level, but I constantly had to prove something that I had already demonstrated. I needed a change of scenery and new challenges, a chance to look for new things in my life. It is an important challenge. I want to take Napoli to the top.''
