The trainer praised the midfielder for his role in the win against Fiorentina and believes his men are slowly resembling the side for which he is striving.
The Colombian came close to leaving San Siro for Juventus in a swap deal involving Mirko Vucinic before the move fell through and he was crucial as goals from Rodrigo Palacio and Mauro Icardi sealed the Nerazzurri's first away win since November.
"Guarin forgot he was supposed to defend at times but he excelled in the first half," the coach told reporters after the match. "There aren't many players like him around. He just needs to perform consistently over 90 minutes. If he can do that, it will be great.
"Hernanes is a player who knows how to deal with pressure and that's what we needed. He's got the composure and class to make those around him play well.
"I thought we were excellent in the first period, especially considering the side we were up against. If we'd made better use of the chances we had we could have won by a bigger margin.
"When we're on our game we start playing the sort of football I want to see."
The win is Inter's second consecutive victory, which sees the San Siro side consolidate fifth place in Serie A.