The South Korean has been a success on Wearside since his loan move from Swansea, but he found himself on the bench when the Black Cats played Liverpool on Wednesday night.
The 24-year-old pulled a goal back in his side's 2-1 defeat at Anfield, the fourth time he has scored during the current campaign, and he feels he has learned an important lesson after a poor performance against Norwich in which he was hauled off after 40 minutes.
"My opinion is that my performance at Norwich was not as good as it has been," he told the Sunderland Echo.
"Maybe, I needed to come out and watch the game from outside the pitch. When I came on, I just tried my best. Sometimes players don't perform and they have to go onto the bench. It happens to all players. I didn't take it badly.
"I want to be more positive after the Liverpool game. But what I have to do is help this team to win and get three points. That's it. Nothing else. It doesn't matter if I'm on the bench or out of the side."
Sunderland have nine games remaining, but Ki will not be able to play in the final fixture of the season against his parent club in what could be a relegation decider.
"I just want to keep this team in the Premier League. I only have eight games left now."