Hernandez made the comments as Swansea get set to host Benitez's Napoli in the Europa League Round of 32 on Thursday night.
"I used to see Rafa at the training ground and the way he worked with players," he told the South Wales Evening Post.
"He used to make sure that the young players had a lot of work so it was possible for them in the future to play for the first team.
"He did great work with the team, to win a Uefa Cup and two Spanish titles with Valencia is not easy.
"It's a good record to have, he was a big manager in Valencia and I have a lot of respect for him."
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