AT 16 years and 10 months old, Fraser Fyvie broke the record held by David Goodwillie by more than a month in Wednesday night's 3-0 romp at Hearts, capping a series of mature performances since he broke into the side this season.
And he followed that up this afternoon by signing a new contract which ties him to the club until 2013.
But his landmark 24 hours will not prevent his team-mates continuing to treat him as the baby of the squad, according to Diamond.
"Last year, he was still doing his homework and now he is going down to Tynecastle and scoring on a big stage," the defender said.
"We need to get him out of his shell because he is quiet.
"Fraser still sits in the visitors' dressing room. I don't think he is getting into the first-team one until he is 18.
"He still has to clean Mark Kerr's boots."
Diamond, who did not make his own Dons debut until he was 17, added: "He has a long, long career ahead of him if he keeps himself right.
"It is brilliant to have him in our team. It just shows the skill and attributes he has because they have enabled him to keep his place."
Diamond has seen plenty of youngsters come through the Pittodrie ranks in his time at the club and had a word of warning for Fyvie.
"There is always a lot of hype surrounding the players because we are a one city club," he said.
"Fraser hasn't made it yet - it is the next season and the season after as well.
"You need to keep going because the pressure that is put on you is remarkable up at Aberdeen.
"He is 16 and I am sure he has broad enough shoulders to take things on board."
Despite his previous contract having 18 months to run, Dons boss Mark McGhee had been trying for some time to get Fyvie on a longer-term deal amid reported interest from England.
Diamond said: "I'm sure the gaffer can take him on to the next stage and then he will have his pick of clubs."
Diamond believes Fyvie will inspire fellow youngsters like Nicky Low, who made his debut as substitute last night.
"The young guys have to look at what Fraser has achieved," he said.
Diamond also came off the bench for his first appearance since the opening day of the season.
"It was brilliant - it has been a long lay off," said the 24-year-old, who suffered a facial injury shortly after recovering from an ankle problem.
"I went out and warmed up and the fans were chanting my name.
"It makes the hairs on the back of your neck stand up."
Source: Team Talk
Source: Team Talk