Roma had no answer for a rampant Real Madrid, who eased to a 3-0 win in their opening Champions League Group G match.
A magnificent Isco freekick put Los Blancos ahead just before the break, then Gareth Bale doubled the lead, while also killing any chance Roma had of getting back into the game, by finishing a swift counter attack.
Mariano made his first appearance since rejoining Real Madrid and bagged a third late on.
As a result, Roma’s record in Spain continues on a dismal track, as they have now lost on five of their last six trips to Iberia, the exception being a 4-0 success at Villarreal in the 2016/17 Europa League Round of 32.
Real Madrid made their intentions clear from the off, as Bale tried his luck but fired wide, then Luka Modric played in Isco who was denied by Robin Olsen.
Continually under pressure, Roma struggled to create anything of note in the first half, with Marcelo then Sergio Ramos going close just before Isco struck with a wonderfully placed set-piece.
It was more oneway traffic in the second half as Real Madrid turned the screwed and a brilliant through ball from Modric sent Bale in on goal, with the Welshman making no mistake, and firing past Oslen into a far corner.
Olsen was called into action, first from Toni Kroos then Mariano, while also producing a wonderful stop to deny Marco Asensio. But Mariano took the ball past Kostas Manolas and curled one into the top corner in the dying moments, further adding to Roma’s misery.
