Courtois also admitted the Blues' mentality has changed under new manager Guus Hiddink, who is now unbeaten in three games after Sunday's 3-0 win at Crystal Palace.
The victory leaves Hiddink's men nine points off West Ham in sixth and 13 adrift of Tottenham in fourth but the performance suggested they may yet be capable of a late surge towards the European spots.
Chelsea host Scunthorpe in the FA Cup third round on Sunday, before league games at home to West Brom and Everton, and Courtois insists all is not lost.
"Obviously if you win the FA Cup or the Champions League maybe it will still be a positive [season]," Courtois said.
"Success is a big word if you play until now not very well except the last three or four games.
"But still with the FA Cup or maybe the Champions League it could be a positive season if we end up in the top four or top six.
"We have to go step by step
Some teams are close together
If we beat West Brom and Everton we could be maybe eighth or ninth in a few weeks.
"Everything can change very fast, we just need the results."
Oscar, Willian and Diego Costa were all on the scoresheet at Selhurst Park for Hiddink's first win since being appointed as Jose Mourinho's successor just over two weeks ago.
Costa and Oscar, both struggling under Mourinho, now have five goals between them since the Portugese left while Cesc Fabregas, another to lose form earlier this season, was also much-improved against Palace.
"It's something psychological and sometimes it changes with little changes
Maybe we needed a little change to pick up our level," Courtois said.
"In football it's always like that
When results are not good the first thing they look at is the manager
But I don't think it is only the manager, the players have to take responsibility as well.
"We were the ones who were not playing as well
With a new manager some things changed
Maybe with some players the mentality changed."
Courtois added: "We of course know we were responsible as well
We had team meetings where we said, 'okay, the manager has gone, but we are responsible as well and we need to pick up our levels because we are not good enough for being a Chelsea player'
Now we are stepping up our game."
Hiddink led Chelsea to FA Cup glory when he took temporary charge at Stamford Bridge in 2009 and the Dutchman already appears to have imposed a sense of stability at the club.
"Obviously training is a little bit different - the approach he has sometimes in how he wants to train," Courtois said.
"Maybe sometimes a bit more tactical, a bit less, different types of little games we play or shooting the ball to give confidence to the strikers.
"Sometimes he is more outside of the training, more observing and leaving the training more to (assistant first team coaches) Steve Holland and Eddie Newton.
"He just steps in when he thinks he needs to explain something to the team
When he explains he explains it well
Every manager has his way of working."
Chelsea want to add their former striker Didier Drogba to the club's coaching staff but negotiations have proven difficult, given the 37-year-old remains under contract with Major League Soccer at Montreal Impact.
"I had a very good relationship with him last year
He was great for the dressing room and our team," Courtois said.
"If he comes back as a coach it will be a great addition to all the team."
Source : PA