The two sides were drawn in Group B with Swiss champions FC Basel and Bulgarian newcomers Ludogorets, who reached the group stages for the first time following a dramatic penalty shoot-out win over Steaua Bucharest.
Liverpool inflicted a 5-0 aggregate defeat on Real to progress to the quarter-finals of the competition in 2009 and Ronaldo knows his team-mates face a difficult task against Brendan Rodgers’ side.
“It’s a fantastic team, last year they very nearly won the Premier League,” he said.
“We know it’s going to be a very tough game at their home (ground) so it will be tough but I think in the general group is nice and I think it’s going to be good for Real Madrid.”
The former Manchester United player won the competition with Los Blancos last season after Real Madrid beat city rivals Atletico 4-1 in Ronaldo’s home city of Lisbon in May.
The Portugal captain is confident his side can defend their title and become the first team in history to retain Europe’s premier club competition.
“We’re going to try and do the same (as we did last season) and try to win the Champions League,” Ronaldo added.
“We know it’s a hard competition to win but we’re going to try. At Real Madrid we’re always thinking big, we’re always thinking huge so we’re going to try.
“We know it’s going to be tough but I think it’s possible to win it again.”
Ronaldo was also named as the Best Player in Europe 2013/2014 following the Champions League draw in Monaco.
The 29-year-old, who beat Bayern Munich duo Manuel Neuer and Arjen Robben to the accolade, could not disguise his delight at winning the award for the first time in his career.
“I’m really, really happy so I have to say thank you to my team-mate because without the team individual awards would not be possible,” he said.
“I have to thank my family, my friends and all the people working with me.
“I don’t have this trophy in my museum so my brother is going to put it in my museum straightaway!”