Crespo says one of those occasions was as a coach.
"In 2002, I was at Lazio and it was either me or Ronaldo who would go to Real Madrid," Crespo told The Tactical Room. "They bought Ronaldo, and I went to Inter as his replacement. If Ronaldo had stayed at Inter, I would have signed for Madrid.
"The second [chance to go to Real Madrid] was in January 2009, in José Mourinho's first season at Inter. Madrid came in for me, but they were only offering a six-month contract, because they had [presidential] elections coming up. I didn't accept it."
When Carlo Ancelotti left Paris Saint-Germain to take over at Madrid in 2013, Crespo could have taken his first steps as a coach as number two to the Italian.
"I watched games [for Ancelotti when he was at PSG]," the 44-year-old, now a youth coach with Parma, said. "I compiled reports and gave him my vision of teams. I did it a number of times, watching the games on TV at home.
"The plan was that I'd be his assistant at Real Madrid, we'd talked about it. But [Madrid president] Florentino Pérez wanted to appoint [Zinedine] Zidane in the role, and let's just say that was a good decision."