The Holland midfielder, signed almost two years ago from Bayern, has been a key influence on Liverpool's Premier League winning campaign this season.
Neppe was involved in Bayern signing Gravenberch from Ajax in 2022 and told Sky Deutschland: "I'm really happy for Ryan. He's a special midfielder. When we bought him from Ajax we were really 100 percent convinced.
"And honestly we never doubted his qualities. We knew that one day they would come to light. We saw exactly what he's showing now at Liverpool.
"Sometimes you need patience. His first season at Liverpool wasn't easy either. It's about momentum. There are so many stories in football about great careers that start with someone else's injury. That they then take their chance.
"Look at Alphonso Davies , the start of his career at Bayern was because David Alaba and Lucas Hernández were injured at the same time.
"He took his chance. But it's not luck. In the end, players like that always show how good they are."