Benitez has been unable to call upon his skipper for all of his 10
matches in charge, but they have conceded just eight goals in his reign thus far.
Their last two matches have also seen them combine back-to-back victories and clean sheets in the Premier League for the first time in more than a year.
Benitez said: "Everyone knows they are good players and the key is the understanding between them is better now and, a little bit, we are adjusting movement and positions.
"You can see that the team is improving in defence but also it is creating chances in attack and this balance is the key for a top side - so you have to have more clean sheets but still score goals.
"The main thing for me is that if you have a clean sheet and can score goals,
that is perfect.
"To be strong in defence is part of the game and, after, you try to play football and go forward and create but you cannot avoid being a proper team in defence.
"Since I have arrived, we have been working with different defenders. Obviously, JT was not here and we have used Cahill, Ivanovic and David and all of them have done a great job.
"Working with these players and trying to change their movements is just a question of spending hours on the pitch at the training ground and you can see the difference.
"If we continue working hard and he continues working as hard as he is doing now and is keen to learn, he will improve.
"How much, we will see. He is good in the air, can play the ball and is quick
so he is just has to adjust some movements and he will be even better.
"I think he has to learn from everyone around. JT obviously has experience but Ivanovic is very strong as a defender and David Luiz has good positioning and good movement so he is learning from everyone and hopefully he can improve a little bit every game or every week."
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