The former Sporting boss, now in charge of Portugal, put the Real Madrid forward on the road to Old Trafford by starting him in a 2003 friendly fixture.
Football is full of ifs and buts, but what if Cristiano Ronaldo had not started for Sporting as they took in a friendly date with Manchester United in 2003?
How different could things have been for the three-time World Player of the Year had he not been thrust under the Red Devils’ nose?
United had, of course, been monitoring Ronaldo for some time before making their move, but his eye-catching efforts in a pre-season contest led them to hurry transfer negotiations along.
The rest, as they say, is history, with a gangly teenager transformed at Old Trafford into a global superstar and a player deserving of a world-record fee when moving to Real Madrid in 2009.
Ronaldo was, however, supposed to have started his breakout game against United on the bench, with Ricardo Quaresma pencilled in from the off.
His subsequent move to Barcelona forced Sporting coach Fernando Santos into a rethink, with the now Portugal boss unaware of the consequences his tactical tinkering would have.
Looking back, the man who guided Portugal to Euro 2016 glory over the summer admits that, from a purely selfish perspective, he wishes he had kept Ronaldo on the fringes of the fold and ensured that he remained part of his plans in Lisbon for a little longer.
“I was his coach when he played against Manchester United,” Santos revealed at the Lisbon Web Summit.
“I put him in the team and now I regret it. One week before, I had lost Quaresma to Barca, two days later it was him off to Manchester United!
“I never expected that thirteen years later I would be champion – alongside both of them – in charge of the national team.”
Santos is now working with Ronaldo again at international level, with the 31-year-old having achieved enough in the game to become virtually untouchable and used in a role which allows him to express himself.
That was not always the case, though, with Santos admitting to having been tough on a man highly fancied to take the 2016 Ballon d’Or during his younger years.
He added: “When I arrived at Sporting I told him: ‘with me you’re always going to play, but you have to stop these circus tricks’.
“And, ‘you’ve got things to improve: you jump really high but you never score headers’.”