Courtois claims they have learned from Jose Mourinho's disastrous 2014-15 campaign when it all went wrong for the reigning champs and the manager lost his job.
He said: “Obviously after last week, it shows it won't be the same. We just started bad. Maybe we need as a group a little wake-up call and say: 'Look, we need to give 150 per cent this year and not 100 per cent.'
“That's what we did. I think we did very well. You see that in the end. We can win those difficult games.
“I remember two years ago we had to go to Manchester City and lost there, and it was a difficult start for us. Now, this victory is good.
“Next week we play at home against Everton, who are doing well. We don't have the easiest start but this victory is good for the confidence, to continue the hard work we are doing in training.
“Can we defend our title? We will see. The Premier League is very long. Last year we didn't start very well, we won the first games then we had a difficult September.
“Then a lot of people said we couldn't win the league, and we did it. The Premier League is one long marathon, not a sprint of one month or two months.
“Let's see, game by game, and then in May hopefully we are there to win the league. If not we will try to be as close as possible."