The Reds are already seven points off United on the Premier League table after seven games. A loss is incomprehensible, even at this stage of the season, and Salah is wary of the brevity of the situation that his teammates are facing.
"It's a big game on Saturday, everyone in the world will watch the game," Salah told the club's website.
"It's a big game for us too because we have to keep fighting and improve our results, as I said. I hope we can get the win.
"We always fight in each game, but this game is a big game and can make a difference for us. We have to improve our place in the table. We have to fight and try to win the game."