The Brazilian celebrated his first goal on Sunday by performing a backflip to remind Lazio president Claudio Lotito of what he was missing.
"It's not like me, it was an unfortunate somersault," Hernanes told reporters. "I feel bad for the fans but I wanted to show Lotito he was wrong after he said he did a great deal when he sold me.
Hernanes was Lazio's outstanding player until he was surprisingly sold in last year's January transfer window to Inter, where he has struggled to settle.
"I feel better than ever and I want to show the Inter fans what I can do," he added. "It was a special match and I wanted to put in a great performance."
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"I wanted to show the Inter supporters that I'm better now and that the real Hernanes wasn't just the one we saw in a Lazio shirt."
The win lifted Inter in seventh place, two points adrift of sixth place where they need to finish to qualify for the Europa League next season.
(The story was refiled to fix a typo in the first paragraph)
(Writing by Brian Homewood in Berne; Editing by Amlan Chakraborty)
