Girona, if we look deeper, don't have too good defense compares to Real Madrid. They got 13 conceded goals so far but their attacking power is amazing. They have 25 goals and is a most goal productive in top five of La Liga, even more than Real Madrid.
This is Girona second season in La Liga after a long time in the 2018 season. Just look at last season, they were able to finish in 10th position. So it is not surprising that this season they have managed to improve their performance again and have been consistent in the 11 matches they have played, only losing once to Madrid. Girona cannot be underestimated by any club. The point productivity alone shows Girona's seriousness.
In fact, Girona doesn't need to have many good players, therefore the coach perfects his players to cover their respective weaknesses. Girona does not need to be compared with Real Madrid because it is clearly not comparable. Maybe with other clubs like Atletico Madrid, it would still be worth doing.
I am sure that this season Girona will be eyeing the opportunity to compete for Champions League tickets.