The 21-year-old Brazilian has started both of Chelsea's Premier League games so far this season; a 2-0 opening day triumph over Hull City - in which he scored the opener - and Wednesday's 2-1 win at home to Aston Villa.
Monday's game sees Jose Mourinho take his side away from home for the first time in his second spell at the club, and Oscar maintains that the Blues are targeting the full three points.
"It's obviously a very important match, and the first of two in succession with Manchester United and Bayern Munich, which are clearly big for us," Oscar told the club's official website.
"It's true it's only the start of the championship but we can't be complacent. This is such an important game and we're sure if we put everything into practice all we are planning in training we can get the three points which will be great for us.
"They are one of the best teams we will play against, one of our greatest rivals and undoubtedly come the end of the season they will be fighting for titles. For this reason we know we need to play well.
"We know it will be difficult but nevertheless we know we can win at Old Trafford. We did it last year and we'll hope to accomplish the same this year."
Oscar arrived at Chelsea from the Brazilian side Internacional in 2012 for a fee in the region of £19m.