An early goal scored by Lionel Messi helped calm any Barcelona nerves after the tie hung in the balance following the 1-1 draw at Stamford Bridge.
Chelsea grew into the game, playing as well as anyone else has managed at the Camp Nou this season, but will have been disappointed when more Messi magic exploited a loose ball in midfield, allowing him to assist Ousmane Dembele's first goal, scored on 20 minutes.
Still, Chelsea's heads did not drop, and they looked determined to stretch the game and come from behind to score two away goals, just as they did in 2012. They put Barcelona under pressure, but with some last-ditch blocking from Samuel Umtiti and Gerard Pique, they were kept at bay.
Their night was done when Messi drove forward and slotted through Courtois' legs a second time to make it 3-0.
Here are five things we learned...