Having won the first leg 2-0, Real peppered the visitors’ goal, but Roma had better chances with Edin Dzeko and Mohamed Salah particularly wasteful.
That proved costly as Ronaldo crashed in at the near post before setting up James Rodriguez for an angled finish, reports the BBC.
Roma hit the post but Real made the last eight for a sixth successive term.
With Zinedine Zidane’s team 12 points behind La Liga leaders Barcelona, winning the Champions League remains their only realistic chance of silverware.
And although they impressed in attack, their casual approach to defence, particularly from left-back Marcelo, will give more clinical teams hope.
And in the second game of the night, German side, Wolfsburg completed the double 1-0 over Gent of Belgium for a 4-2 aggregate score to also reach the last eight.
CHAMPIONS LEAGUE RESULTS
Real Madrid 2-0 Roma (agg 4-0)
Wolfsburg 1-0 Gent (agg 4-2)
