Real have dominated Europe's elite club competition with five titles over the past four seasons, taking their overall tally to 13.
The Spanish giants have torn up the history books in the ruthless manner of ousting some of their European rivals but with the departure of attacking talisman Cristiano Ronaldo - it could be one of the most open tournaments in recent history.
But who will step up and end the Los Blancos monopoly?
The LaLiga champions will be desperate to lift Europe's most coveted club honour this season after several seasons of disappointment.
With Lionel Messi leading the charge, the new club captain will be motivated to get his hands on the trophy that's eluded the Blaugrana since the 2014/15 season.
Barca's latest acquisitions may not have been the most high-profile but the promising signings have increased their depth - while Phillipe Coutinho will be a major addition to their attacking ranks in this season's competition.
Last season's finalists were left to rue the injury of Mohamed Salah in Kiev and with a significantly stronger squad under Jurgen Klopp, the Reds will be brimming with confidence.
The front-three of Salah, Sadio Mane and Roberto Firmino netted a staggering 28 goals and the additions of Naby Keita, Xerdan Shaqiri and more importantly goalkeeper Alisson - will further stake their claim for top honours.
PSG's spending power over the past five seasons have made their intentions clear.
They want to be crowned European champions.
Under new management of Thomas Tuchel, Neymar, Edinson Cavani and Kylian Mbappe will be taken to new levels with the high-pressing attacking approach.
Pep Guardiola created one of the most devastating Premier League sides in history last season as the Citizens romped to the title in record-breaking fashion.
However, it's clear that his intentions are now firmly set on securing the title that's eluded him since his days at Barca.
Like PSG, bankrolled by Qatari billionaires, the Champions League has become the main target for the demanding owners and Pep will need to deliver.
The club-record signing of Cristiano Ronaldo, a five-time Ballon d'Or winner and five-time Champions League winner has indicated what Massimo Allegri has been set out to achieve this season.
Ronaldo's goals often proved the difference during Real dominance over the past five seasons and he's likely to be the key figure for the Italian giants who want to replicate their domestic dominance in Europe.