"We start a new era with the full confidence that the arrival of our new coach will make us stronger," said Perez.
"Your name is a guarantee of hard work. We have one of the best coaches in the world."
Benitez is returning to Spain for the first time in over a decade after making a name for himself with two league titles in three years at Valencia between 2001 and 2004.
Yet, he has failed to land a league title in the 11 years since he swapped Valencia for Liverpool.
Benitez's greatest achievement in that time came in winning the Champions League in his first season at Liverpool. However, he delivered only the UEFA Super Cup and the FA Cup in 2006 in the five years that followed at Anfield.
A nightmare experience followed at Inter Milan where he lasted only six months as Jose Mourinho's successor and another short-lived unhappy spell at Chelsea followed as he was never accepted by the fans despite winning the Europa League in 2013.
A two-year spell with Italian giants Napoli also came to an unsatisfactory end on Sunday with a 4-2 home defeat to Lazio which ensured they did not qualify for next season's Champions League.
And Benitez is fully aware that he has to deliver success immediately if his stint in his dream job isn't to be a short one.
"Undoubtedly this is the highest quality squad I have coached," he added.
"It is different to when I arrived at Liverpool. There was a project there for three years to compete and try to win something. Thankfully, in the first year we won the Champions League.
"Here we need to compete and win from the first moment. We have to always be competing and we will only be satisfied with victory. The expectations are very different, they are much higher than when I arrived a Liverpool."
-AAP