Heynckes guided Real Madrid to victory in the Champions League final over Juventus 14 years ago and duly left the club within 48 hours.
Di Matteo has transformed Chelsea's season since taking over as caretaker manager after Andre Villas-Boas was sacked in March, but there is no guarantee he will be offered the job permanently even if Chelsea are crowned European champions for the first time.
Although Chelsea won the FA Cup earlier this month and are now within 90 minutes of what would be their greatest triumph, the signals emanating from Stamford Bridge indicate that the club's billionaire owner Roman Abramovich wants a more glitzy, bigger name to fill the role.
Heynckes, 67, one of Europe's most experienced and successful coaches, who would become only the fourth man to guide two clubs to European Cup success, thinks letting Di Matteo go would be a mistake.
"I think the position of Chelsea and Di Matteo can be understood. Chelsea are a huge club, a top club in Europe, and you will try to find the best possible coach, someone who has already won something and already brought titles and has all the attributes you need for this kind of job," he said.
"But Di Matteo makes an excellent impression on me and if I was Abramovich, I would continue with this young man.
"He led Chelsea to the final with a calm head, and step by step he established contact with the players. I think really, until today, his work has been outstanding and no matter if they win or not, I hope he stays there because there is a need for continuity."
Di Matteo's position has been strengthened since he began to breathe new life into Chelsea's season after Villas-Boas's departure, and all he has said in response to hundreds of questions about his future is: "lets wait and see."
