I know the six points Girona is leading Athletic Bilbao with are enough for Girona to finish in the top four of La Liga. But their current performance has made them drop a lot of points in a short time, and if they continue to perform like that, Athletico Madrid and Athletic Bilboa will close the gap with Girona in the La Liga table. Girona needs to improve their performance and start winning matches to remain in their third position in the La Liga table.
The six points is actually enough if only Girona will be able to maintain it because it take loosing Just two matches and they will be ripped of that six points difference, they will have to maintain a winning streak or possibly a draw at worse, that way they will be able to still maintain their position within the top four position on the table but if they fail to maintain winnings or draw they may stand the risk of loosing their position to either Barcelona or Bilbao.
Bilbao is currently in a very sound form such that we can not underestimate what they are actually capable of as at this time, they are very much Capable of been able to close the gap much more than we would be thinking of them, although I'm aswell aware that Girona has been of a considerable good performance which can even be seen as above average, so it's still possible they will be able to literally want to maintain their position well enough and not been displaced my other teams.
Girona has recently not been in their very best form as they were at the beginning of the season so it time they actually beginning to make sure to sit up else they may not be able to finish at the second position but they are very likely to still stay within the confines of the top four and finish as such to be able to qualify for the champions league next season which I think will be an achievement for them cause not often have they qualifed for the UCL.