Everyone literally predicted Bayern Munich to win because they haven't lost since the season but Mainz humbled them to their first defeat in the Bundesliga. Had it been Eintracht Frankfurt won their match against Leipzig yesterday, they would have closed the gap but for now Bayern Leverkusen has picked the race against Bayern Munich as they are just 4 points behind. Mainz is a weaker team when compared with Bayern Munich but if you check their form this season, it is not bad and they are 7th in the league table which means they are one of the average teams in the Bundesliga. Fatigue also affected Bayern Munich players after they lashed Shakhter Donestk 5:1 when they met in the Champions league last week. The absence of Harry Kane due to a thigh injury he sustained in their game against Borussia Dortmund also made the team to lose a bit confidence because since his absence, they have played four games in all competitions, won two and lost two.
Apart from the previous season when Bayern Munich failed too much, in the other seasons they tend to win most of the time and lose few games and the teams that defeat them used to be those in the middle of the table like Hoffenheim and the others. I wouldn't be surprised to see them losing against Mainz this time and they still have some security gap.
Dortmund is the one that is suffering a lot in Bundesliga this season and should try to fix things otherwise they will be out of all European competitions..