The Blues host the Foxes on Saturday and United next weekend and Courtois feels it is vital they pick up all six points.
Chelsea are seventh in the table with 13 points and they have struggled against their likely title rivals to date, with defeats against both Liverpool and Arsenal, and Courtois feels it is vital they make a statement in their next two games.
The Belgian also hopes he can keep another clean sheet after a 2-0 win over Hull last time out but he says wins are more important.
“Obviously it’s always nice to keep clean sheets but it’s not the most important thing,” Courtois told the club’s official website.
“It’s good to not concede because then you know you only have to score one goal to win the game, which is good, but I would always rather get a victory than draw 0-0 and keep a clean sheet for myself.
“It does give you confidence, though, and hopefully I can keep another one against Leicester to help us win the game.
“We have two big games coming up against Leicester and Man United and we need to win them if we want to stay near the leaders. They are direct opponents in terms of finishing in the highest places so it will be good for us if we can do that.”
Gary Neville has defended Jose Mourinho and believes Manchester United's style of play was not always great under Sir Alex Ferguson.
Liverpool will want £90m plus Real Madrid duo Dani Ceballos and Keylor Navas in return for Mohamed Salah, reports have claimed.
Tottenham boss Mauricio Pochettino is being linked with a shock move across London to Chelsea as a replacement for Antonio Conte.
Brighton boss Chris Hughton has been rewarded with a new contract after keeping the Seagulls in the Premier League.