'Now that all the basics are clear let's start then, What I'm about to show you is the cultivation method for fire element it was once used by a friend of mine who obviously wasn't a match for me but could still hold his ground.'
Here comes the bragging. At this point, Vishnu didn't even think that all this bragging could be true. Like how he once used the sun to cook food or whatever. But even so, if this old man is saying that this guy could hold his ground against him so that means they should be equal in power at that time.
"Yeah Yeah" Vishnu just half-assed his response otherwise the old man wouldn't stop.