"He was moved [by the photo]," the Atletico Madrid boss explained. "A lot of memories from 26 years ago came flooding back. He had come to Italy to see me playing in Pisa and, at the time, he was 46, as I am now." History, Diego thought, has a funny way of repeating itself.
Sunday was another case in point. Sixteen years after Diego had netted the only goal in Lazio's crucial Serie A clash with Juventus in Turin, his son played an even more prominent part in Genoa upsetting the Old Lady at the Marassi.
After just three minutes of play, the ball dropped for Giovanni in the Bianconeri box. His first effort was saved by Gianluigi Buffon but the striker, exhibiting the kind of persistence of which his father would have been proud, made no mistake at the second time of asking to put Genoa a goal to the good.
Just over 10 minutes later, Giovanni struck again, this time stooping low to head home a cross from the right flank from Darko Lazovic. Genoa would add another goal before the break as they became the first side since AC Milan in 2005 to go in 3-0 up on Juve at half-time and, even though Miralem Pjanic reduced the Old Lady's arrears with a trademark free-kick, the hosts held on quite comfortably to claim a famous win.
For Simeone junior, though, it was an even more significant game. Giovanni had proven his pedigree by firing Argentina to victory at the 2015 South American Youth Football Championship, netting nine times in nine appearances, while he had broken his Serie A duck with a goal against Pescara on September 25. However, a double against the reigning Italian champions was something special for the Simeones.
"This is the best day of my career so far," he enthused, while his father took to Twitter to express his joy at emulating his achievement in taking down Juve.
EMOCIONANTE pic.twitter.com/7Jcz3WW9ar— Diego Pablo Simeone (@Simeone) November 27, 2016
The Simeones' joy was understandable, as few had anticipated Giovanni making such a swift impact in Serie A. The 21-year-old had joined Genoa from River Plate in August but it had been his performances at Banfield that persuaded club president Enrico Preziosi to pay €3 million for the striker with the famous father.
Giovanni scored 12 times in 29 appearances during a loan spell at the Estadio Florencio Sola but he nonetheless arrived at Genoa expected to serve as an understudy for Leonardo Pavoletti.
Diego, though, was optimistic about his son's chances of succeeding in Serie A. "I'm happy that my son is in Italy," the Atleti coach told the Gazzetta dello Sport in September. "He can learn and improve there. It's not easy but he has the necessary qualities. And good blood in his veins!"
Obviously, the pair are very different players. Diego was a hard-running, tough-tackling midfielder, the driving force behind domestic doubles for both Atletico Madrid and Lazio, and two Copa America triumphs for Argentina. Giovanni, meanwhile, is a strong, technically gifted No.9 that former River Plate and Banfield boss Matias Almeyda believes can be "the new Patrick Kluivert".
However, ex-AC Milan defender Alessandro Costacurta says that Giovanni is not as different to Diego as many believe. "His father was a tough guy and I took several elbows off him," the former Italy international mused. "And I can see that Giovanni is clearly Diego's son by his character..."
Giovanni is understandably desperate to be his own man, though. When asked after Sunday's win over Juventus, if he will become an even better player than his father, he replied: "No, I'm just Giovanni, a guy that always wants to grow and improve."
However, he is well aware that having Diego's DNA is no bad thing. "I heard from my father [before the Juve game]," Giovanni revealed, "and he told me he had scored against Juventus and that, therefore, it was in our blood, so I had to do the same!"
Now that he has realised that goal, he looks set to score many more. As he showed on Sunday, Giovanni Simeone is more than capable of making a name for himself in Serie A.