The Swans struggled to break down a resolute Sky Blues defence and had to be content with just a point from the game at The Liberty Stadium on Tuesday night.
"It wasn't a good game but they closed all the spaces and it caused us problems," Swans boss Sousa said after the match.
"A lot of teams come here to defend and today I could see that we need to react more quickly.
"Not every team will defend as well as they did but we made some bad decisions and must learn to keep possession better."