"It is only a matter of time before he gets called up for England," said Benitez.
"He is learning a lot, he is working hard, he is more mature and I think that soon we will see him in the national team.
"I have no doubts about Pennant's quality," said the Liverpool boss. "He is playing really well.
"This is the kind of player we were looking for, someone who can beat players, can cross and can give to us more options on the right side where we had problems last season.
"You must have a lot of respect for the other managers, and if they want to select other players then you must respect their decision.
"The only thing you can do is to support your players and tell them they need to work harder."