Daniel Farke said Dominic Calvert-Lewin is "like a good wine" following the in-form striker's call-up into Thomas Tuchel's England squad.
The 29-year-old has been included in the Three Lions' squad for their upcoming Nations League matches after scoring four goals in six appearances in all competitions this season.
He was given a standing ovation by Leeds fans as he was withdrawn late on in Monday night's 4-1 win against Newcastle at Elland Road, while Sky Sports pundit Jamie Carragher described him as "unplayable."
Farke said: "Dominic is like a good wine, getting better by the year. Physically, he's on a top level and his pace is more than good enough I would say. He's a very complete striker."
Calvert-Lewin arrived at Leeds on a free transfer from Everton in August last year and when asked where he ranked among his best-ever signings, Farke said: "At Leeds while I've been here we've made many top signings on a low budget.
"When I think about Joe Rodon, Ethan Ampadu, Ao Tanaka. It's difficult to compare because as a striker you have a different role. But he's definitely one of our better pieces of business.
"If you come as a free agent it doesn't mean it costs no money because there's a salary. But we believed in him when perhaps not many were doing this.
"He also believes in himself and he believes in Leeds United, so I would say he was a perfect fit."
Farke has been dealt an injury blow as his side bid to extend their unbeaten Premier League start to five matches at home against Crystal Palace on Sunday, with summer signing Harry Wilson ruled out with a thigh injury.
"Sadly, Harry Wilson is out for this game with a quad injury. He had some problems after the [Newcastle] game. He'll also probably miss Wales' [Nations League] games."
Confidence is sky high at Elland Road after Monday's win lifted them to the dizzy heights of third place in the table.
Leeds have lost just five of their last 29 league games stretching back to last November, with only four other clubs collecting more points during that period.
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Farke added: "It's no coincidence. If you deliver over a long-term period it's not just a good period, it's quality.
"Everyone can be proud, but nothing is taken for granted. Momentum can change quickly. We're fully aware if we think we are 'big time,' it's the first step to failure.
"The table is not important. Eight points after four games is good, but not what we want to achieve. Want to win 40 points as quickly as possible and our only aim is to make sure we win that."
