The two teams have met each other 12 times since 2000, and the Blues hold the better head-to-head record, winning four, losing three and drawing five in the modern era.
And two of the most famous encounters, at Stamford Bridge in 2005, and Camp Nou in 2012, were the stage for two of the best goals ever scored in the Champions League.
Brazilian legend Ronaldinho lit up London 13 years ago, jinking and twisting on the edge of the Chelsea box before firing home through a throng of defenders, leaving fans of both sides utterly bewildered.
His compatriot Ramires followed suit more recently, stunning the Camp Nou into silence with an utterly delightful lob from a seemingly impossible angle as the Blues drew 2-2, earning a spot in the final in the process.
As we've done throughout this season's Champions League, we put the goals to two famous faces, Spencer FC and Seb Carmichael-Brown of Hashtag United, and asked them to put forward their cases in My Goal of the Week, brought to you by Nissan. Watch their debate in the video above.
And now it's your turn to decide: Ronaldinho or Ramires?
Have your say now!