Although stressing City’s season should not yet be regarded in those terms, and he is thinking positively, Pellegrini recognises missing out on Europe’s elite competition would be bad for the club.
And City, who only just missed out on a place in this year’s final as they were beaten at Real Madrid in midweek, still have work to do to secure their entry for 2016-17.
Manchester United and West Ham are both hoping to leapfrog fourth-placed City in the Barclays Premier League and Pellegrini’s men face a crucial game against third-placed Arsenal on Sunday.
Pellegrini said: “If you are not in the top four and in the Champions League the next year, to demonstrate you are one of the best teams in England, then for me it’s a disaster of a season.
“That’s why I always said last year, when we didn’t win any titles, that it was not a disaster.
“It was not a good season but a disaster is when you are not involved in the next season’s Champions League. That is a disaster for all the big teams.”
But he added: “I always think in a positive way, so I hope that we are going to be in that [top four] position.”
Pellegrini also qualified his remarks by saying there was a way a top club could salvage their season if they missed out.
He said: “Of course, if you don’t win and you’re not in the top four positions of the Premier League and you win the Champions League, FA Cup and Capital One Cup, it’s a very good season.”
For Pellegrini, who is making way for Pep Guardiola at the end of the season, qualifying for the Champions League again is now a matter of pride.
He has been stung by suggestions that, because he is leaving, he was prepared to risk top-four status to pursue this season’s European challenge.
He said: “I think it is very, very important to arrive to the Champions League next year. I finish my contract here but that is not a thing I am worried about. I don’t understand those kind of speculations.”
City’s failure to mount a serious challenge for the title and their manner of their defeat at the Bernabeu — where a 1-0 scoreline flattered Pellegrini’s men — has left a negative impression on the season.
But while Pellegrini admits expectations were higher, he thinks the campaign should be looked on positively.
Speaking at a press conference, he said: “You always feel that you can do it better, especially for me. I am disappointed not to win the Premier League this year because until February we were in our best moment to do it.
“But we won one title – the Capital One Cup – and I hope we are going to finish in the spot of the Champions League for next year. It is a season I think you can improve on, but it was not a bad season.”
Pellegrini, who was appointed in 2013, now has just two games left in charge of City. He has made no decisions about his future but would consider staying in England.
He said: “I always say it is maybe not the best football but it is the best league. To continue here, not at Manchester City but in the Premier League, will always be an important option.”
“But as a manager you must try to dominate your emotions. Of course I have feelings but don’t want to show them in an external way.”