He added: "I am always confident and we need to do a good job on Wednesday and get through to the next round. The players are training very well and I will need to select the best players I have available for this game."
But boss Rafa admitted that taking a clean sheet to the BayArena would have made the job in hand much more straight forward.
"I said after the first game at Anfield that 3-1 was a good result but 3-0 would have been better and there is no room for complacency. We will try to score a goal over in Germany," he said.
"I think the first 20 minutes of the game will be very important and if we can control the game it will frustrate Leverkusen. We will need to start with a high tempo because they will start with high intensity. They have good forwards and when they play at home they always score goals. What we have to do is defend well and score ourselves," Benitez added.