Shelvey was outstanding in the 2-2 draw, though his errors led to both of Liverpool's goals.
"It will make him stronger, it does happen in football," said Wales skipper Williams. "Jonjo will definitely learn from it. I am sure he will.
"I've made mistakes but not on that stage, Monday night football, the whole country watching, against your old team, it doesn't get any worse.
"Those mistakes will stick with him for a little while, but the good thing about football is you've always got a training session coming up. "The lads have already taken the mickey out of him a little. It won't be with him for too much time, but it hurts at the time.
"It's an honest mistake, you can't have a go at him. I'd rather have a go at someone that didn't give 100 per cent. He plays with emotion so I knew that it was going to affect him a little bit. For a 21-year-old it was a good performance.
"I said at the time I thought he was a good signing for us. He brought something I believe we haven't had before at this club.
"I think he still needs to settle in a bit more to the way we play, but that's natural. For someone who gets on the ball as much as he does, I think he's going to be a very exciting player for us."
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