"When you are so young and if you do not have this spirit, it is very difficult to do something," Fabregas declared.
Fabregas, who missed a decent chance to level during the first half, added: "We have to be strong and at least we have come back fighting until the end.
"This is the most important sign. We are still at the top, we have to be strong. We have to try to be there until the end."
Despite seeing their five-point lead over Manchester United cut to only one, Fabregas maintains there are still plenty of reasons to be positive as the campaign enters a crucial phase, with AC Milan next up on Tuesday night for a place in the Champions League quarter-finals.
"I don't think there is any reason to be down," insisted the Spanish playmaker.
"Four weeks ago, we were two points behind Man United, then we were five points in front, now we are one point but still at the top. I don't think that is bad.
"Chelsea have 25 international players, Man United won the league last season, they have a great team.
"We are young and we are there, so we have to look at the positives, not the negatives."