Scales' header was the game's only goal, helping the champions return to winning ways.

O'Neill praised the Irishman as "exceptional" since his tenure began, particularly in defence.

He also bantered that Scales sometimes tries to emulate the Argentine football legend.

The 74-year-old said: "Scales has been great for me, honestly, really great.

"Sometimes Scalesy plays a pass as if he was Messi, and that doesn't happen.

"But he's been fantastic.

"I'm sure he's been a fine player before I came here, but in my year here, he's been absolutely exceptional.

"I couldn't speak more highly of him.

"I think he's great for us defensively.

"He's a centre-half, but sometimes I'm expecting him to play the ball like an inside forward or something like that, but overall he's been really terrific.

"He's come up with some big, big goals, but he's also come up with big, big moments defensively for us during my time.

"He's strong, he wants to do it, and come up with goals for us as it turns out, the most important goal today."