The champions started their new season with a home defeat to the Clarets, but bounced back in impressive fashion at the weekend after recording a 2-1 victory over last year's runners-up Tottenham Hotspur at Wembley Stadium.
Many have doubted Chelsea's credentials to retain the title this season, but Courtois is confident that his team will be in the mix come the end of the campaign.
"Maybe we need as a group a little wake-up call and say 'look, we need to give 150% this year and not 100%.' That's what we did against Tottenham, I think we did very well," Courtois told reporters.
"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. 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."
Chelsea won the 2016-17 Premier League title with 93 points from their 38 league matches.