Mourinho once called Paris Saint-Germain's Zlatan Ibrahimovic one of his own during his time at Inter Milan, and on Wednesday night, they will face each other as rivals, each hoping to end the other's European dream.
Indeed, as the teams line up at Parc des Princes, the contrast between the strikers on both sides couldn't be any more significant.
Should Chelsea look to sign Zlatan Ibrahimovic this summer?
For the French champions, Ibrahimovic has fired home a staggering 40 goals this term—10 in the Champions League alone. It's a return that dwarfs the combined tally of all three of Chelsea's recognised front men (25).
Add Edinson Cavani into the equation and the gulf in class in that department is clear, with Samuel Eto'o, Fernando Torres and Demba Ba all having struggled for goals at various stages for the Blues this term.
There's no doubting PSG's strengths with their strikers, although Chelsea themselves have talent elsewhere in their squad that ensures this quarter-final with the Parisians is going to be an almighty contest.
Mourinho's team has been impeccable defensively this season and further forward, the likes of Eden Hazard and Oscar carry a considerable threat in midfield and will cause PSG significant problems.
It's been up top where Chelsea have remained weak, and the sight of Ibrahimovic limbering up in PSG colors will have Mourinho ruing his team's shortcomings.
After all, he must now wait until the summer before adding a player of Ibrahimovic's class to give Chelsea a better chance of competing with the Premier League's elite, let alone Europe's.
So, why not make Zlatan that man?
On the surface, it's a rhetorical question. The Swede is one of the world's finest players and unlike many of his peers, he has the talent to back up that inflated ego of his.
In reality, though, it's a dream that has the potential to become a nightmare—and fast.
If Chelsea ever desired acquiring Zlatan's services, that ship sailed a long while ago.
It was Karl Marx who once described religion as "opium for the masses"—the notion being it helps all those who believe forget the reality in which they live.
At 32, Ibrahimovic would very much serve the same purpose at Stamford Bridge.
He may come with the wow factor, but bringing him to West London would merely paper over cracks. His time at the top, in the way we know him now, is rapidly decreasing with each passing week.
For all the furore and excitement his arrival would bring, Chelsea wouldn't have to wait too long before finding themselves exactly where they are now—stuck with a big-name striker, earning world class wages and incapable of scoring the goals that deliver titles.
It's tempting to think otherwise; of course it is. This Ibrahimovic, maverick footballer who appears in a class of his own at times. But Chelsea have hopefully learned from their past mistakes.
In many ways, the striker Mourinho targets this summer could be the most significant signing of his Chelsea career.
He needs to be pragmatic in his approach, forgetting profile and star appeal to bring in a front man who fits—a forward to make the impact we saw Didier Drogba have throughout his Chelsea career.
As great as he is, Zlatan doesn't fit that mould. The reality is, his days are numbered.
The Swede has every chance of winning the coming battle for a place in the Champions League semi-final over this next week, but avoid the lure of pursuing his talents and, in time, Chelsea will win the war.
Garry Hayes is Bleacher Report's lead Chelsea correspondent and will be following the club from a London base throughout the 2013-14 season. Follow him on Twitter here @garryhayes