The Spain international has been heavily linked with a big-money transfer to Manchester United in recent weeks as Louis van Gaal looks to bolster his defensive options at Old Trafford ahead of his second season in charge at the club.
United are understood to have already had a bid rejected for the defender as Van Gaal looks to tempt the centre-half into a move to the Premier League.
However, despite conceding that things could still change, newly-appointed Real Madrid boss appears to have all but ruled out the possibility of the Spanish side cashing-in on the defender.
Benitez is quoted as saying by the Daily Mail: “Sergio Ramos is our player and he is a key player for us.
“I would like to see him at the beginning of the season playing for us. I think he will be crucial for us during the season.
“I am 100 per cent. I insist it’s clear for me and for the club that Sergio will be here.
“I have a lot of respect for [United manager] Louis van Gaal and football is a curious world, but Sergio Ramos will stay with us.”
Louis van Gaal has already made four signings this summer in a busy transfer window.
The Dutchman recruited Netherlands international Memphis Depay in a £25m deal from PSV Eindhoven in May.
The United managed has also added Germany international Bastian Schweinsteiger, Torino full-back Matteo Darmian and Southampton midfielder Morgan Schneiderlin to his squad.
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