The race for the Liga crown will go down to the wire after both teams failed to secure victories at the weekend, with Barca hosting the current league leaders in the final round of fixtures.
A draw would be enough for Atleti to claim a first Spanish championship since 1995-96, but Sosa - on loan from Metalist Kharkiv - has revealed that he and his team-mates will be going for the three points.
"We have to keep fighting to the end," said Sosa, who provided the assist for Atletico's equaliser in a 1-1 home draw with Malaga on Sunday. "We will be full of energy and have our heads held high.
"The whole team is showing that we have the character and the strength for this season finale.
"We have two options but it would be a mistake to go there and try to hold on for a draw."
Sosa has made 14 league appearances for Atleti this season.
