The 52-year-old Spaniard admitted he could not have foreseen taking over the hot-seat at Stamford Bridge so quickly, but says he is prepared for Premier League action once again
The former Liverpool boss will take charge of the Blues against Manchester City on Sunday afternoon after replacing the Italian coach, with his last role coming in 2010 with Italian side Inter.
But, despite being out of a coaching job for two years, the 52-year-old has revealed he has been preparing for a return to management, and is hungry to succeed again.
"You are not expecting to be here, and that Chelsea would have to change the manager in that time," he told the club's official website.
"When they decided to do it I talked with my agent, and I knew we had a chance, but everything has happened very quickly."
Benitez has been working hard away from management, and while the Spaniard has taken on one of the most difficult jobs in football, he is eager to prove himself once again.
He continued: "I have been quite busy, watching games, analysing games, doing a website, writing a book and developing coaching programmes, so I was very involved with football and ready for this time.
"When you are some time without training you want to do well and succeed again. The game has not changed a lot in that time."
While he has managed teams in Spain and Italy, Benitez revealed he is happy to be returning to a job in England, and is relishing the prospect of setting up in the capital.
"I was in England, my family was settled down, and my priority was always the Premier League, so I was trying to stay around," he added. "Obviously I was going to Spain, Germany, wherever, but most of the time I was here.
"I was in Madrid for so many years. It's a big city, but obviously London is bigger - in a big city you can find everything you want."