Ez Abde struck for Betis before FCK equalised from the penalty spot through Kevin Dijks.
Pellegrini later said: "A hard-fought match, especially in terms of ball possession, which they have a lot of. Once we had it, we tried to hurt them, but we couldn't get the second goal. It's two points lost, but this is just the beginning . There are four games left and we are going to achieve the objective of qualifying.
"We are playing against two important rivals in their leagues; one who beat us on a corner and this one, who tied us on a penalty. The objective is to qualify and I am sure that in the four games left we are going to achieve it.
"I want to qualify. If we are in the top eight, all the better, but if we have to play an intermediate round, it's not a problem. If we qualify in the top eight, we'll save a couple of games, but my goal is to qualify and I'm sure we'll achieve it.
"The important thing is to be committed to this season. We know what we have to do, to qualify. You can't always get the three points, although we deserved them today. Adrián didn't have a single shot on goal."