Betis - Barcelona is such an interesting match that both of them can be the winner at the end of it. Because Betis are also one of the teams that are having an incredible season. This is their biggest success in the La Liga for so many years. And they still have a chance for even joining the Champions League. They mustn't turn this opportunity down that easy. As Atletico Madrid also have a very difficult match against Real Madrid, I think Betis have a big opportunity to catch up with them maybe. I'm just thinking of betting on both teams to score and enjoy the match. 
Barcelona needs to win against Real Betis otherwise I don't think they will be able to hold onto their second position in the standings.
But this match is surely not going to be an easy one because Barcelona has been a little inconsistent in recent times just like Real Betis, so I don't know what will be the outcome of this match but as Barcelona don't have any other things to worry about right now accept for La Liga, I think they will apply there best strength to win this match.