Clarke is on-loan at Stoke from Tottenham.
O'Neill told Stoke-on-Trent Live: "I thought he was very good. You can see straight away his ability on the ball. He can handle the ball very well. I thought he linked very well with Nathan Collins on that side and Joe Allen.
"That's two very young players who handled it very well against two very good players on that side. It was a good start from Jack.
"In the three games since he's come in he's shown great quality and I think he can add something to us."