FRANKFURT, Germany — With the public still jittery after the Paris attacks and the security alert in Belgium, misbehaving fans are the last thing any football club would want right now.
Despite tighter security, Bayern Munich fans made the headlines after getting involved in brawls in Gelsenkirchen at the Bundesliga match against Schalke. Police detained nearly 200 people.
Next up for Bayern is Tuesday's Champions League home match against Olympiakos, which could not even get a game in — its Greek league match against bitter rival Panathinaikos was called off because of crowd trouble.
So Munich police will also have to be on the lookout for troublemakers from both rowdy fans.
Matters should be calmer on the pitch. Bayern and Olympiakos will both advance from Group F with a draw. A Bayern victory will ensure Pep Guardiola's team wins the group.
Arsenal hosts Dinamo Zagreb in the other match, with each team needing to win to remain in contention and help from either Bayern or Olympiakos.
An Arsenal victory coupled with an Olympiakos defeat at Bayern would give the London club a chance of finishing second. Arsenal visits Olympiakos in the final group match. Dinamo needs to win and hope Bayern loses to keep alive its slim hopes of sneaking into second place — it would then have to beat Bayern by more than five goals.
Here are some other things to know about Group F:
The Bavarian powerhouse is unbeaten in the Bundesliga, which it leads by eight points after collecting a league record 37 points from 13 games. Pep Guardiola's side has only dropped two after starting with 10 wins.
Bayern didn't play particularly well against Schalke on Saturday, but displayed great resilience and determination to seize the lead through Javi Martinez before eventually winning 3-1.
A draw would suit both teams but the Greek champions will be warned — Bayern has managed at least four goals in each of its last six home games.
Midfielder David Alaba could miss the match after picking up a left-ankle injury against Schalke.
ARSENAL ON THE BRINK
A lengthy injury list is nothing new for Arsenal. Usually Arsenal drags itself through the Champions League group stage with little trouble. Not this season. Not with midfield shortages more acute than ever for Arsene Wenger's team.
Francis Coquelin and Mikel Arteta were both injured in Saturday's 2-1 loss at West Bromwich Albion. The defeat is not so damaging in Premier League terms — Arsenal is only two points off top spot in fourth — but further failure against Dinamo on Tuesday would spell the end of the Champions League campaign.
For 15 consecutive seasons Arsenal has reached the last 16 in Europe's premier competition. But the Gunners host Zagreb six points behind Bayern Munich and Olympiakos with two games remaining in a campaign that began with a loss in Zagreb.
The only high point of the campaign has been beating Bayern at home. Finishing third would see Arsenal relegated into the Europa League and it could even face the ignominy of bottom place. Exiting Europe, though, would allow Arsenal to concentrate on trying to collect the Premier League trophy for the first time since 2004.
"If you ask my deep gut feeling, I want to stay in the Champions League," Wenger said. "We will give absolutely everything to stay in the Champions League.
"I think we still have a strong chance but it will be very tight now."
Dinamo has never progressed from the group stage and travels to London amid a scandal shaking the club.
Club president Zdravko Mamic and his son have been arrested on embezzlement charges, accused of pocketing money personally from transfers of Dinamo players. Dinamo's coach is Zoran Mamic, the president's brother.
In addition, midfielder Arijan Ademi has been suspended for four years for doping after testing positive following Dinamo's 2-1 win over Arsenal in the home leg. It was its first win in 16 years in the competition.
"A lot of things have to come together for us to create another surprise but we believe in ourselves. Arsenal is the favorite for sure but favorites don't always win," said Dinamo forward Junior Fernandes.
The unexpected weekend break leaves the runaway Greek league leader with fewer injury worries ahead of the match in Munich, as captain Giannis Maniatis and Argentine playmaker Alejandro Dominguez return to fitness.
The Greeks are pinning qualification hopes on their final group match against Arsenal at home on Dec. 9, and coach Marco Silva has told his players to enjoy their trip to the Allianz Arena.
"It's not about being afraid of Bayern or Guardiola, but we have to admit that they are probably the best team the world at the moment — or at least one of them," Silva said
"So it'll be a difficult night, but more about effort and belief in ourselves than fear."