David Ngog got the only goal at a packed Elland Road to see the Reds through to the last 16 of the competition, subsequently ending Leeds' 15-match winning streak on home soil.
Benitez had named an unrecognisable starting Xl, with Javier Mascherano and Jamie Caragher the only first-team regulars in the line-up.
Still, the Reds' second string put up a decent performance against a determined Leeds side who were unlucky in defeat.
Leeds had their chances and were hard done by when having a goal disallowed early on for offside.
Asked if he thought that was the turning point in the game, Benitez shrugged, telling Sky Sports: "I haven't seen the replay but from what I saw in the game we had our chances and they had theirs too.
"It was a typical cup competition game."
PraiseKeen to praise the opposition, he added: "It was important for the players to play well and work hard it was a very difficult game and credit to Leeds they played fantastic.
"Playing against a top side in the Premier League we knew would be massive for them.
"We knew it would be tough but the response from the players was fantastic tonight."
Asked how important it is to progress to the next phase, he said: "You need to win every game to get to the final.
"We know that we have to win and that is our target."