Icardi moved to Inter this summer from Sampdoria.
"Guarin put such a good ball at my feet, so the only thing I could do was put it in," grinned the Argentine on Inter Channel.
"I broke my duck, as I hadn't scored yet in pre-season and I now have the satisfaction of scoring my first goal for Inter.
"We played a good game, though it was of course more difficult than the work we've been doing in training. Now our legs are starting to get into gear and we have a better rapport on the pitch."