"He is a professional and every professional gives the best for the club, the players, for everybody".
The three previous players to do so are Robbie Fowler, Michael Owen and Wayne Rooney - so he is the first foreigner to rack up so many Premier League goals at such a young age.
A late Romelu Lukaku double and an Enner Valencia strike securing a convincing win for Everton, which will be remembered especially fondly by academy product Calvert-Lewin.
"Everybody loves Rom", Koeman said of Lukaku, who has just over two years remaining on his current deal.
"To do that, you need the platform to show yourself", he said when asked about his desire to be ranked along with the world's best forward.
Earlier in the week the Belgium worldwide told the club he would not be signing a new £140,000-a-week contract that would make him the best-paid player in their history as he questioned whether they had the ability to reach the Champions League.
With Kevin Mirallas in Belgium for the birth of his child, Calvert-Lewin made his second league start this season and the 20-year-old took full advantage with the opening goal in the first half at Goodison Park.
Speaking about the game, Koeman told BBC Sport: "It's great of course, you like to be confident at home". But we spoke about the six points in the two home games against West Brom and Hull.
Manchester United and Chelsea have been given fresh hope in their pursuit of Romelu Lukaku after Ronald Koeman revealed that the striker will have the final say on whether he leaves Everton this summer.
"It's always very hard to always take the best decision".
