I mean if Barcelona or ATM wins their extra game (they are at 19 games played, Girona had 20) then that means the difference will drop to just 5 points, which isn't really a whole lot, just two games out of all the other games worse than them and they are lower. I keep telling people that last games of the season are the hardest ones but people ignore that.
Barcelona and ATM can surpass Girona because differences are not too big and they are more experienced than Girona. In a long season, they also have more advantages than Girona because they have more players to alternate for their squad than Girona. It will be more helpful for Barcelona and ATM through a long season but I of course, don't exclude disadvantage of two big clubs as they will have to play in Champions League. They will have to play more matches than Girona and it contains more risk on their players to be exhausted or injured.
Anyway, in general I really believe that Girona will nearly impossible to complete this season in top four, not yet mention about their chance to win La Liga title against Real Madrid. Even if they won't complete this season in top four, this season will be marked in their club history as one of most amazing seasons.