Both teams enter El Gran Derbi in questionable form.
But Pellegrini says: "I see the team in good shape. Of course it would have been much better to win in Europe, it's a competition we have to qualify for, we'll see in December if we're qualified, losing a few games won't matter. We'd all like to win every game, but it's not possible.
"This is different, it's LaLiga and when you lose points, you lose them for good and you go down the table, and even more so when it's against your biggest rival like the derby in Seville. Mentally the team is doing well, with a League with fewer points than we deserve, but you don't have to deserve the points, you have to get them. And then with the peace of mind of taking two days to rest and being in the best possible shape."
On toning down the pre-derby euphoria, he continued: "Of course we can, we've done it in previous derbies. It's a game where, no matter how much you try to control your emotions, the atmosphere in the stadium often leads you to make mistakes.
"It's important to keep a warm heart and a cool head, not to make mistakes, get sent off, get penalties or fall into any kind of provocation. I hope we have the maturity to avoid getting sent off and to be able to capitalise on the chances we've had in previous games."
On the need to win the derby, Pellegrini also said: "I always want to win every game. If the ones that Betis fans suffer or enjoy the most are against Sevilla, of course I would like to beat Sevilla. We have played very good games in previous derbies, but we have not managed to win. We did in the Copa del Rey.
"The objectives have to be a priority, the priority is the objective of the entire season. We have to try both things. Hopefully we can achieve it tomorrow because it would put us in a very good position in the league table, we would give the fans something to cheer about and we would continue to improve in terms of football."