The Italian struck in victory over Capital One Cup opponents Swansea City this week.
"It's more of a confidence thing," Rush told Sky Sports News HQ. "Maybe being on the bench took a bit of pressure off him. Maybe he felt a bit more relaxed.
"People are always quick to have a go at someone like him when it's not going well, but I think you have to believe in what he's doing and hopefully this goal will give him the confidence to do that.
"I'm not saying it's going to change straight away, but what I'm saying is as much as people want to write him off too quickly when he's not scoring, he was getting the chances he was getting them there, and I don't mind that if you're missing the chances. He's doing something right."
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