Goal exclusively revealed that the Premier League club’s technical director Michael Emenalo was in Croatia earlier this week trying to tie up a deal for the 18-year-old, who starred in this season’s Uefa Youth League against Arsenal and Bayern Munich.
However, despite being very complimentary about the manner of the negotiations, Mamic explained that Chelsea’s bid has been politely declined.
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“For the last few days, Chelsea representatives have been in Zagreb, where they have prepared - I must admit - a great offer for Adrian Semper,” he said.
“We thanked them [for the offer]. They were highly professional and pleasant people, but we said ‘no’.
“It is never easy to reject such a big offer for a young player, but we are convinced Adrian has a fantastic future ahead of him and we want him to spend at least some of that future with Dinamo.”
Chelsea’s opening offer of £1.9 million was quickly rebuffed by the Croatian club, but Goal understands that the Blue returned with a second offer in the region of £3.1 million.