The Spaniard has been embarrassed twice before in the competition, by Burnley and Barnsley, and does not want the Royals to complete the hat-trick of Championship sides producing an upset against him.
"We know the FA Cup is a massive competition, so we want to progress and go forward as much as we can," said Benitez, who won the FA Cup in 2006 against West Ham at Cardiff's Millennium Stadium.
"Our priority now is one game at a time, so the first one is the most important.
"The FA Cup is a very good option for us to win something this year, so we have to approach the game thinking about winning.
"It would be very special to get to Wembley. We've been to Cardiff, but now we have to think about winning the first game."
Benitez knows Reading will have drawn more confidence from the first tie than his side, who had won back-to-back league matches prior to the encounter, but he has called on his squad to raise their game to ensure they do not give the Royals a chance at Anfield.
"It was very difficult at Reading. We decided to play with a strong side and it was still difficult," said the Liverpool boss.
"We have to approach the game thinking about winning and not giving them any chances or any confidence that they can do something.
"In the Premier League you have to win but if you can't you say 'unlucky'. But in the cup you have to win."
Source: PA
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