"He's been doing well," Mascherano told LFC Magazine. "Obviously he is a young player so can still improve and get better.
"It isn't easy to be playing for the Liverpool first team at just 20-years-old. I'm really happy for him."
Mascherano added: "Emiliano didn't play first-team football in Argentina, so to come here at such a young age and make the breakthrough is a great achievement.
"It would have been easier for him had he played first-team football in Argentina. Everything was new to Insua when he came here. But after just two years he is playing really well whenever he gets into the first team."