The Argentine defender scored the only goal of the game against The Rams at The Liberty Stadium on Friday night.
"It was a fantastic goal with great quality," Sousa said after the match.
"Fede is improving a lot. He keeps doing well, he's working hard, he wants to improve and is improving himself.
"It's not easy to win these games when one team only defends.
"There was good quality in our game and great attitude once more.
"We have a long way to go, but I think we are getting closer to the right match routine.
"We can be stronger and more competitive."