The four-time MVP re-signed with the side that drafted him in 2003 after a spell with the Miami Heat, but scored just 17 points in the 95-90 defeat to the New York Knicks.
The forward told reporters: "I didn't press, I didn't do much. It was a special night. I'm glad it was great, but I'm also glad it's over.
"I was throwing passes where I thought some of my teammates were. Those things will come. It was one game, and we've got to learn from it."
James spent seven years with the Cavaliers before moving to Miami, where he won two NBA titles, in 2010.