"I don't know but perhaps it's the best game away in 40 years," said Benitez.
"We have played a very good game we have seen the mentality of the players, the team spirit they have and quality."
Fernando Morientes scored his first goal for the club, and John Arne Riise scored the winner in the 2-1 win.
"Fernando played very well, but with 10 players around him playing well, it is easy for him," added the boss.
"We had talked before that he was playing very well between the lines, winning balls in the air.
"But as a top striker you need to score goals and for him it is fantastic."