The enigma of Bayern Munich exhausts itself with needing to win every competitive match they play. The German champions had fans frustrated and bewildered after the 4-1 loss to Wolfsburg on the Bundesliga's return from the winter break, while the home draw with Schalke four days after had fans scratching their heads, looking for solutions.

The Champions League returns to the Allianz Arena for the first time this year with Shakhtar Donestk the visitors after a 0-0 first leg draw. A win is simply a necessity for Bayern, if they want to progress to the quarterfinals.

"This game isn't just important for me. It is important for the club. It's simple: we just have to win the game," said Pep Guardiola in his press conference on Tuesday. "This game is like a basketball playoff, the two teams know each other. In the end, the quality of the players is the difference," the Spaniard proclaimed.

Bayern Munich has only been knocked out of the Champions League at this stage twice in the last decade. Having reached at least the semifinals in each of the last three seasons - with their fifth European Cup triumph coming in 2012/13 - the club's encompassing goal this season, has been to triumph on the biggest stage once again.

After a tight, tetchy affair in Ukraine - in which Bayern clocked up less miles than Shakhtar whose matches have been relocated to Lviv - the home side was able to hold off the rampant Bayern attack, causing the German defense problems on a number of occasions. The Ukrainian's Brazilian attacking quartet of Alex Teixeira, Taison, Luiz Adriano (Champions League top scorer - 9 goals) and Douglas Costa left defender Holger Badstuber impressed following the first leg.

"Pep has tried to give us a few tips. Shakhtar have some great attacking players," said the 25-year old. "You have to know your opponent."

Shakhtar has only recently returned to competitive action, as the first leg of this tie was their first encounter of meaning in 2015. Since then, they have won twice and drawn in the three fixtures, with a late equalizer against rivals Metalist costing them in the league on the weekend. Mircea Lucescu, the Shakhtar coach, will still be without Bernard in Munich, with a thigh injury.

Following a hotly-discussed win over Hannover the weekend, the Bundesliga champions will be aware that a loss on Wednesday would leave their so far dominating season in ruin. With the Bundesliga title now likely to head their way, the task for Bayern is to conquer Europe once again. A fall at the first hurdle would be catastrophic for the team's reputation amongst Europe's best.

Despite returning to team training this week, Philipp Lahm won't feature in the tie. Javi Martinez (knee) and Thiago (knee) have also begun light training, but remain out, as well as Xabi Alonso who is suspended following his red card in the first leg.