The Spaniard, who scored twice as the champions beat Newcastle on Saturday, is ineligible for the game against the Bavarians but has the utmost faith in his teammates.
The 25-year-old is ineligible for the Red Devils after representing Chelsea earlier in the season but is hopeful of another English side returning from Bavaria unbeaten, following Manchester City and Arsenal’s exploits.
After opening his account the previous weekend, Mata scored twice as United beat Newcastle on Saturday and the club-record signing highlighted the importance of momentum as the team prepare to travel to Germany.
"It's a key victory to try to climb the table and go to Germany full of confidence," Mata wrote on club's official website. "This victory gives us a lot of energy for our game in Munich on Wednesday.
"I'll be supporting from home, in front of the TV, aware that the Allianz Arena is one of the toughest stadiums in Europe ... but also aware that we are Manchester United and I'm sure we can make it through!"
Mata is delighted to be finding his feet at his new club and says he is enjoying his football again after struggles for United and himself personally this season.
"I scored and enjoyed on the pitch again," he wrote. "I wish the streak goes on until the end of the season.
"The truth is, after a game like Saturday's, I realise once again how nice football can be, and how much you enjoy the few days following a victory and a good performance."