Real Madrid overcame Milan 3-1 in the Bernabeau, but must still beat Lokomotiv in Moscow next week to ensure passage into the last eight.
Borussia Dortmund remain just one point behind the Spaniards after they eased past Lokomotiv last night.
Real coach Vicente Del Bosque admitted it would not be an easy task.
‘It’s still going to be very difficult,” he said.
“We have to prepare for a tough matchin Moscow next week and there is still plenty of hard work to do.”
Real dominated the game from the start. Raul became the first man to hit 40 Champions League goals when he opened the scoring after 11 minutes, prodding home from seven yards after a Ronaldo lay off.
He added a second 12 minutes into the second half – going past Fernando Redondo and Martin Laursen before firing home. Rivaldo pulled one back for the visitors with just eight minutes remaining but Real substitute, Guti put the result beyond doubt shortly after, when he stabbed home from close in.
The victory gave Real a record 50 wins in the competition.
“We were a little worried after the Rivaldo goal. But luckily Zidane produced a brilliant move to set up our third a few minutes later and that allowed us to relax again,” said Del Bosque.
Milan coach Carlo Ancelotti admitted that he side were not at their best because they had already qualified.
“We did not play with the same urgency as Madrid,” he said.