Despite taking a one goal lead into the match at Anfield on Tuesday, Hyypia knows just how dangerous Madrid can be.
"It will still be difficult because it is just half time in the tie so there is still a lot of football to be played," said Hyypia.
"We have got a lead which is important and we know that if we play as well at Anfield as we did over there then we should be okay.
"But Real are a top side and they will be looking forward to coming to Anfield and hoping to get an away goal of their own, so we will have to be very careful," he added.
"They will still be confident that they can get through and we have to have our own confidence and belief that we can qualify.
"We want to be in the competition for as long as we possibly can but, like I said, it is still half time and there is still a lot of football to be played," he continued.
"We believe in ourselves and of course we believe that we can finish the job but we also know that it will be tough."