Borriello was carrying a knee injury, but still managed to put Milan ahead in their Champions League tie before Marseille's second-half equaliser.
He said: "Up until yesterday I had a swollen knee, which it was a little this morning too, but I knew it was a special appointment and pushed through the pain thanks to the adrenaline of the match."
He passed a late fitness test to start the 1-1 draw with Olympique Marseille and scored a sensational solo effort.
"I think I put in a good performance, scored a goal and didn't lose the ball very much. I could've done better on Ronaldinho's assist in the second half.
"I am very relaxed and above all happy to be playing again, as six weeks ago I was in the stands. Now I am playing, scoring goals and since I came back the team hasn't lost a game.
"It's great to feel the faith of the fans and the Coach. I can hear they call my name more when I step on to the field."