The 29-year-old Argentina international had been a target of criticism during the Magpies' lengthy run of poor results, but bounced back in style at the weekend with a much-improved display and the opening goal in the 3-2 Premier victory over Chelsea.
Pardew told the Evening Chronicle: "Jonas answered a few critics - I thought he was fabulous against Chelsea.
"Everybody gets a lift when you bring new players in and I think Jonas is an example of that.
"He's a good player, but he's been running on empty and lacking a bit of confidence and belief because the team hasn't been strong enough.
"It's disappointing for players like him. Sometimes when you bring new players in it's only right that you give him a chance and say, 'Come on then, we've got a proper team now - come and show your true form'.
"He did that and I'm pleased for him. I'm very proud of him."