O'Neill also gave teen Connor Wickham a start on the day.
He said: "Just at the moment when probably we all need a lift, on comes James McClean and his first move was probably the first time the crowd have seen him, and he was so positive.
"He played brilliantly in the reserves against Manchester United after a sluggish start in difficult conditions on Thursday evening.
"He wants to get at players - he is so positive and he is young, immature - and that was great, and the crowd took to it.
"But I could go through the team. Connor Wickham, for instance, has done two days' training in the five weeks since he was injured.
"The training in the lead-up to the game wouldn't have been that strenuous, so he has done two days and he was great for us considering.
"He's 18 years of age and hopefully he's got a proper career in front of him, but he as was willing as the day is long.
"I thought he was out on his feet, to tell you the truth, but overall, it was a brilliant effort to play the length of time he did."