O'Neil made his full debut in Saturday's 2-2 draw with Sunderland and Downing told the Evening Gazette: "Gary looked good. He is a confident lad and I knew he would do the job because he is fit and energetic and gets crosses in the box which led to our first goal.
"I think with me on the left and Gary on the right we can cause teams problems this season.
"We haven't really had a natural right-sided player for a long time, we just needed that balance.
"We have got Luke Young behind him, who has done ever so well since he came and I've got Tayls behind me on the left.
"So it's good balance and we are a good, attacking force going forward."