Liverpool full-back Andy Robertson believes the Reds gave Real Madrid "too much time" in the first leg.
Zinedine Zidane's side ran out 3-1 winners thanks to Marco Asensio and Vinicius Jr's double.
Mohamed Salah grabbed the visitors an important away goal in Los Blancos temporary home, Estadio Alfredo di Stefano.
Real Madrid were dealt a number of injury blows prior to the first leg with Sergio Ramos and Raphael Varane missing out through injury and illness respectively.
Former Chelsea star Eden Hazard's torrid time in the Spanish capital continues as it was announced he would miss both legs through injury.
A slow start from Jurgen Klopp's side meant they found themselves two goals down at the break.
For the opening goal, Germany midfielder Toni Kroos was able to pick up play in his own half unopposed and set the Brazilian youngster, Vinicius, off behind the Reds back four.
The Scot, speaking to Liverpoolfc.com, acknowledges the 13-time Champions League winners as one of the strongest teams when in possession.
“Real Madrid are one of the best at controlling games. When they’re in winning positions, they’ve got the likes of [Luka] Modric and [Toni] Kroos that can just stand on the ball for what feels like 10 minutes and you can’t get it off them,”
Asensio was cool and calm in his finish lofting it over the onrushing Alisson before poking home into the net after Trent Alexander-Arnold inadvertently headed into the Spaniard's path.
As Liverpool began to grow into the first leg, lapses in concentration allowed for the 20-year-old to ghost in between Alexander-Arnold and Nat Phillips to fire through the defender's legs into the back of the net despite Alisson's best efforts.
“But we need to put these players under pressure, we need to put them all under pressure, we need to make their life a bit more uncomfortable than we did last week. It felt as if we gave all of them too much time on the ball, really, so we need to make it uncomfortable for them." Robertson said.