There was a time when even to suggest such a thing would have forced you to suppress a derisive snort. To state with any level of credibility that Atalanta - one of Italy’s perennial elevator clubs, shuttling back and forth between Serie A and B - could trouble a member of Europe’s elite like Real Madrid would have provoked nothing more than a chuckle of disbelief. However, like a gig by a bad stand-up comedian, nobody’s laughing now.
It still, in truth, stretches the elastic of your credulity to see the fixture pop up on the Champions League list. Anyone who ever visited Bergamo would struggle to imagine the place - as pleasant as it is - providing a football team to challenge possibly the biggest outfit our continent has ever produced. And yet, just maybe, the boys in blue and black could be capable of springing an almighty surprise. Here are five reasons why it could be possible.
No Papu, No Problem - Atalanta have always been about more than any individual player with a system which sees a few stars sacrificed most summers in order to rebuild with more modest acquisitions.
Nonetheless, when things turned sour with Alejandro Gomez, some suggested they were losing the very mechanism that made this precise football watch tick. However, their form since he last appeared for the club suggests that they are hardly missing him at all.
One defeat in 16 matches has kept them on the fringes of a thrilling Serie A title fight and seen them make serene progress to the Coppa Italia final. The little Argentinian might well be thriving in Sevilla, but they have shown few signs of nostalgia at his old club.
Muriel’s Magic - He has always been a streaky performer, but the Colombian forward has hit an ominous run of form which could spell trouble for a Real Madrid defence shorn of many of its most established performers.
His pace and cunning have outwitted many a back line of late - Napoli his latest victims - in a stellar season. He is on course to surpass his own league goalscoring record and his strike rate per minute played is truly remarkable. Bergamo seems to be bringing the best out of a player who has known his highs and lows in the past and he is just the sort of footballer who can tear any team apart when he is in the mood. Look out for Luis.
Wide Boys - It is no secret that Atalanta like to attack on the flanks and they might have two of the best marauding wide men in the game. Robin Gosens and Hans Hateboer have tortured defenders up and down Italy with their pace and attacking intent and will be looking to wreak similar havoc on the Madrid back line.
The Dutchman has been struggling with injury and looks set to miss out on the first leg at least - Joakim Maehle his likely replacement - but the wide areas remain a key angle of attack for the Serie A side.
In theory, the Spanish team should have the tools to disarm them and force them into defensive duties but that might be easier said than done. Ferland Mendy and Lucas Vazquez - or whoever fills the full-back roles - will have to be on the top of their game to fend them off.
Smarter Side - A lot of people fell in love with the Lombardy lads last season with their swashbuckling run to the later stages of the Champions League which only narrowly fell short against Paris St Germain in the quarter finals.
What made that run all the more remarkable was just how badly they had started the competition with three defeats - two of them extremely heavy - in their opening group games. However, they are quick learners and have adopted a more pragmatic approach this time around and - while still prone to the odd calamity - they look much more assured this season.
They will still be the undoubted European apprentices compared with their illustrious opponents, but their relative lack of experience does not mean they have not got pretty savvy quite quickly. In short, don’t expect this particular David to be overawed and overpowered by Goliath.
The Fitness Factor -When the draw was made the Madrid giants would have been significant favourites to progress, but the treatment table has not been kind. Reading through the injury list at the Bernabeu takes about as long to digest as War and Peace these days and Zinedine Zidane will be forced to play a makeshift side.
Atalanta, in contrast, have just about all their options to choose from apart from the ailing Hateboer. Such are the reserves of talent at Real that they will still be able to select a starting XI more than capable of getting a result, but their injury crisis certainly narrows the gap a little. The Italian side have made their relentless attacking approach a calling card in the past few years and they are likely to test any weaknesses in the visiting line-up to the full.
Los Blancos are still the more likely to win over the two legs - of that there can be little doubt - but the challenge presented by Giampiero Gasperini’s side is certainly not the kind they can dismiss lightly. Only time will tell who will have the last laugh.