Of course, 3 points must be obtained by Barcelona to reduce the gap in points. Currently their points difference is 4, if they lose, Barcelona will be further and more difficult.
If Barcelona still wants to join the race for the title, they need to shorten the point gap. Yes, the point gap is 4 now, they need 3 points to shorten the point gap with Girona at least. Barcelona needs to overtake Girona first before they target to overtake Real Madrid in the first place. This is the scenario of Barcelona for competing the title.
I feel pretty sure if Barcelona can get 3 points. In terms of quality, Barcelona players are superior. In addition, the performance of Barcelona players is in good condition after winning against Atletico and qualifying for the UCL knockout phase.
Of course, Barcelona has more quality players and they will play at home as well. Winning the match and get 3 points are a must, they won't share points with Girona. 3 points in this match will be very crucial, it will keep their hope for the title. If Barcelona fails to get 3 points in this match, we can assume Real Madrid will be the champion this season.