The Reds find themselves well off the Premier League title pace after seven games, sitting seventh in the table following Sunday's 1-1 draw with Newcastle United at St James' Park.
Mignolet admits to being 'frustrated' by the result after Liverpool again squandered a number of good chances in front of goal, but the Belgium international believes that lessons have been learned heading into the United clash on October 14.
"If you come away with a 1-1 result, that's obviously a disappointing feeling," he told the club's official website. "You start to look at what you could have done better. We played well, we deserved to get the victory, we created chances. But it is how it is at this moment in time, we have to take it.
"It's disappointing and frustrating, but we have to keep looking forward, keep our heads up and make sure when we come back after the international break we go again against Manchester United, which is a big game and something to turn things right for us. Everybody will be away in another environment and when they come back, we've got that one to look forward to.
"I'm sure everybody will be focused on their international duties now, but when they are back they have a big game to look forward to. We will be ready for it. When we're creating chances, the ball never falls in front of us. But we have to battle through these moments and we have to keep working hard.
"At one point, these balls will fall for us and we might score a lot of goals. At this moment in time, it is how it is. It's not that we're not playing well. We're still playing good football and creating chances. We have to capitalise on them and be more efficient."
Liverpool have won one of their last seven games in all competitions and trail Man United and Manchester City by seven points.