Barcelona could get la liga title couse Real play against Sevilla, and they are good team, also they have more games to play so players will be tired. Also there is Malaga, and they are in very good shape, maybe better than Sevilla 
did you mean Real Madrid cannot defeat Sevilla because they are too tired after playing for semifinal match against Atleticoi think you're wrong and i believe they could do that because Real Madrid home matches results during this season was pretty good
and as the strong team in spanish league they able to manage their performance