Sully had been missing since August with a fractured thumb but looked sharp as he was tested to the full by the Gunners who won the FA Premier Reserve League encounter 3-0 at Stevenage Borough FC.
"He looked good," said Colin. "We knew it would be a game where he would have something to do, in the end it was more than we would have wanted and he was tested.
"He would have enjoyed the saves he made, three or four reaction saves and that's an indication that he's getting his match sharpness back. It's good for him that he's come through.
"In fact Sully coming through the game and making those saves were the highlight of the night."
Reserve team boss Colin Calderwood was full of praise for Neil Sullivan after the goalkeeper's successful return to action against Arsenal on Monday night.