The Manchester City manager believes the Liverpool striker - who scored four goals against Norwich in midweek - has improved his game, but the Argentine is a more rounded talent.
The Liverpool man jumped ahead of his Manchester City counterpart in the top-flight scoring charts on Wednesday after netting four goals in a comfortable win over Norwich - taking his tally to 13 in nine outings.
Pellegrini ranked Aguero behind ony Lionel Messi and Cristiano Ronaldo in the world last month, and he has reiterated that belief - but feels Suarez has improved his game of late.
"Suarez is a very important striker, but I think Sergio participates more in the game," Pellegrini is quoted as saying by the Daily Mirror. "Sergio is just 25-years-old, so I think of course he can improve. I think this year he has improved a lot in the way he works during matches.
"He has always been a top player and he has always scored goals, but I think at this moment, he has added working for the team without the ball, which is also important for him. I never said he was the best striker in the Premier League - I said he was the best player. Maybe there are players who are better strikers than him, but not as complete as him."