The fleet-footed right-back made a €8.9 million summer switch from Marseille to Stamford Bridge and admits he struggled initially with the tempo and physicality of the English game.
But after the controversial appointment of Benitez in November, the Spaniard has risen to the challenge to become one of the mainstays of the Chelsea rearguard.
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"When Rafa came, I learned a lot of things. He taught me about positioning, tactics, reading the game, the best way to do the right things.
"Then I played my first game with the national team this year, so this is important for me. Rafa did a good job here. He gave me a lot of confidence. He tried to do his best with the team."
As the season comes to a close, the 23-year-old has reflected on the difficulties of Chelsea’s congested fixture list, particularly when expectations are so high.
"Playing for Chelsea you have the responsibility to win every game," he added.
"Physically and mentally, it is difficult, because every three days you have a massive game. We are fighting for every trophy.
"It's the first time I have played a lot of games like this. This season I started to play in November and after that it is every three days.
"It feels like we've been playing finals for four or five months now. Every week we have a massive game, in the FA Cup, Capital One Cup, Premier League, Europa League."