After Saturday’s defeat to Hannover it's fair to say that the unthinkable may strike again. Sitting in fourth place and five points behind Mirko Slomka's unfancied side, it's becoming increasingly likely that Bayern Munich, the Bundesliga champions, will fail to qualify for next season's Champions League. The Bavarian giants plight looks likely to cost Dutch tactician Louis van Gaal his job, only a year after delivering a domestic double and reaching the final of Europe's premier competition. So where did it all go wrong for the most successful team in German football history? We look at the five key moments that saw Bayern's season unravel. 1) Arjen Robben And Franck Ribery's Injury Problems Bayern made a disastrous start to this campaign and it was clearly evident that the side were in need of some flair and conviction on the flanks. The two wingers scored a phenomenal 30 goals between them last season from out wide, with Robben grabbing 23 of those. The former Real Madrid man deservedly claimed footballer of the year in Germany, only the fourth non-German to win the illustrious award. The two players also provided 18 assists to ensure a highly successful campaign for die Roten. This season was depressingly different with both Robben and Ribery missing the first half of the campaign with injuries. After matchday nine, Bayern had only scored eight league goals - the lowest tally in the whole of the Bundesliga. It came as no surprise, then, that the team's performance improved considerably when both men returned; the only problem being that cracks elsewhere began to show. 2) Uli Hoeness And Louis Van Gaal Rift Some may say van Gaal's imminent departure from the Allianz Arena was writing on the wall due to a rift between the Dutch coach and club president Hoeness. On October 31 of last year, Bayern legend Hoeness unleashed a venomous tirade on van Gaal after Bayern's disappointing start to the season. Not one to mince his words, the son of a butcher claimed the coach was difficult to talk to and a 'one-man show' - perhaps a strange choice of words to describe a tactician who has brought the club huge success in such a short period of time and has just started to get the side's campaign back on track. The duo did openly kiss and make up, but it's hard to believe that tension between the two is absent especially in recent weeks where Bayern's season has collapsed beneath them. 3) Mark Van Bommel's January Departure A lot has been said this season about Bayern's defensive flaws. It seems every defender at the club has been slated this season due to poor performances, and while there's no smoke without fire, van Bommel's January transfer to Milan has left the Bavarian club looking even more vulnerable at the back. In the six games since the Dutch defensive midfielder left the club, Bayern have conceded 11 goals. The much-maligned 33-year-old may not be everyone's cup of tea but no one could argue that the former Barcelona man provides a welcome shield to any defence. Fans of the club will argue an adequate replacement hasn't been found. Andreas Ottl doesn't have the quality of van Bommel while January big buy Luiz Gustavo has often found himself deployed at left-back, not the defensive midfield role which is his natural position. 4) Home defeat To Dortmund It now seems a distant memory but only a fortnight ago many felt Bayern were still in the title race if they could defeat runaway leaders Dortmund at the Allianz Arena. Victory would have still left the club 10 points behind Juergen Klopp's men, and stranger things have happened in this Bundesliga campaign alone. Instead, reality dawned and Bayern were outplayed in a morale-shattering 3-1 defeat. The reigning Bundesliga champions lost their crown with an almighty 16-point gap emerging between BVB and die Roten. Yet more importantly, the side slipped out of the Champions League qualification places to unfancied Hannover. With a trip to their unexpected rivals coming up the following week, surely FCB would get back to winning ways? 5) Away defeat To Hannover March 5 - the day the unthinkable happened. Bayern travelled to North-Western Germany knowing victory would move the club back in the Champions League spots, and would have been the perfect tonic after the club's midweek exit from the DFB Pokal to Schalke. There was to be no victory. Bayern crashed to a miserable 3-1 defeat, and everything that could go wrong, did go wrong, to leave the champions five points adrift of Mirko Slomka's side. So what next for the Bavarian powerhouse? The importance of next week's home tie against fellow underachievers Hamburg is huge, but even victory may not be enough to rescue Bayern's flailing season. Whether van Gaal will be in charge of the upcoming encounter remains to be seen. What is for sure is that these are some of Bayern's darkest days. (Source: Goal)