Girona's players also managed to perform well against the two giants of La Liga like Barcelona and Atletico Madrid. And they defeated both these teams. Both teams are now far from the top of the table as a result of the defeat against Girona. Madrid and Girona are now fighting for the La Liga title.
Girona scored 51 goals in 21 matches this season. Girona has scored the highest number of goals in La Liga this season. Madrid scored 43 goals in 20 matches. This shows that Girona's attack is very strong this season. And so it is now challenging for any team to win against this team.
Girona has been good not just against smaller clubs but against everyone, however the point would be doing good for all season long as well. You can lose all your games against 2-3 teams, but if you win every single game aside from those, you are going to still end up being the champions, and that is why just a few clubs do not matter, what matters is that Girona rarely ever loses points and they are doing as well as they can imagine.
It's of course a big shock to everyone, if they do somehow end up with the league title, which I still doubt because Real is being protected by the referees at this point, then it would be like Leicester City story, and I think there will be at least a few documentaries about them made for this season.