Having not played for the first team since the final game of last season against Manchester City, the side has desperately missed his consistency and pace at the back. After taking no risks with his recuperation, the England defender believes he has improved his chances of reaching full fitness once again.
"It was nice just to come through 45, my first in six months or so, and it feels good," King told the clubs official website.
"The medical staff have been brilliant and have helped me to get to where I am now. I had confidence in the knee going out there and that is a good feeling.
"I feel fine, it was good to come through it. As long as the knee is fine I am happy."
With King determined to take his comeback slowly; fans should not expect to see him back in first team action just yet. "I've had my fair share of injuries, but this has been the longest one," he added.
"They are all as frustrating as each other, but this has been the one I've had to be most careful with and I had to make sure I was right before coming back so that I don't have any more problems.
The reserve game itself ended 1-0 to Fulham after forward Ismael Ehui struck the only goal of the game in the 90th minute.