The Brazilian forward is enjoying a fine season having taken his tally to 20 goals in all competitions for the Reds.
It has coincided with the absence of Coutinho, who missed chunks of the first half of the season through injury and was then sold to Barcelona in January.
Liverpool manager Klopp does not believe Coutino’s exit has made Firmino better – but it has seen him come out of his compatriot’s shadow.
‘I don’t think he has stepped up but maybe it is more obvious because his situations are not overshadowed by Phil Coutinho’s situations. That’s how it is. That is all,’ said Klopp.
‘He’s a very important player and he doesn’t always have to be the standout player. As often as he can be, that’s good. I don’t think he’s underrated. Not anymore. I don’t know what other people think about Roberto Firmino. I can imagine a bit because you ask me about it. I have no idea. People with a football brain judge him right. That’s how it is.’
More: Liverpool FC
Liverpool take on Porto tonight in the first-leg of their Champions League Round of 16 tie.
The loss of Coutinho might be considered a hindrance to their hopes of success in the competition, but Klopp highlighted the fact the now-Barcelona player was not responsible for Liverpool reaching the knock-out stage.
‘We qualified for the Champions League without Phil, he was not involved in either of the Hoffenheim games [that qualified Liverpool for the group stage]. All the players we have here are fantastic players, it’s about really how we stick to the way we want to play. You have to cause them problems, problems and problems.’