Olympiacos v Atletico Madrid: Simeone's men on crest of a wave
Diego Simeone's men were the surprise package of the 2013-14 competition, reaching the final in which they were beaten 4-1 after extra time by neighbours Real.
But the scoreline did not tell the full story of a game that Atletico led 1-0 until the 93rd minute, when Sergio Ramos' last-ditch equaliser forced extra minutes.
Real took control thereafter with Simeone's side ultimately denied a remarkable double having won La Liga for the first time since 1996.
A close-season exodus followed when the likes of Diego Costa left the club, although Atletico responded by doing some shrewd business of their own.
And Simeone's side have not skipped a beat, following up a two-legged Supercopa de Espana win over Real by picking up seven points from their first three La Liga games.
So impressive have their efforts been that some have suggested that this team is stronger than the one that finished last term.
"I had to say if this team is better or worse because we have different players," said talismanic centre-back Diego Godin.
"Things change but the important thing is that the team continues with the same mentality. That's the key."
The most impressive of those performances came on Saturday, when Arda Turan's goal secured a 2-1 La Liga triumph at the Santiago Bernabeu.
It is, therefore, with huge confidence that Atletico head to Greece to face an Olympiacos side on Tuesday who have also begun this season with two wins and a draw domestically.
The Spanish side will certainly glean plenty of confidence from last term, when they went unbeaten in all six away games - including eye-catching wins against Porto, Milan and Chelsea.
But Olympiacos are dominant at home, epitomised by them winning 16 of their 17 league fixtures at the Karaiskakis Stadium in 2013-14.
Atletico have concerns over the fitness of Cristian Rodriguez, who missed the Real game through a calf injury sustained when on international duty with Uruguay.
The Greek champions are likely to be without Giannis Maniatis, who has been sidelined since August 30 with a left ankle sprain, although Dimitris Siovas is edging towards a comeback from a long-term injury.
Group A rivals Olympiacos and Atletico last met in the European Cup Winners' Cup quarter-finals in 1992-93, when the Spaniards prevailed 4-2 on aggregate.