The Belgian made a fine save to deny Alexander Isak in the clearest chance of the match.
"We can score goals, you see it in training and in the game against Getafe [in a pre-season friendly] at Valdebebas, but sometimes it doesn't come off," Courtois explained to Movistar+.
"Real Sociedad are a good team; we can score goals and they will come."
Speaking about the game, Courtois expressed his happiness with the defensive performance.
"We're happy with the organisation of the team," he said.
"We didn't concede many chances; the problem is scoring goals and the last pass that just won't come off.
"We didn't have many chances, but we created danger."