PSV Eindhoven have apologised to Ajax after Dusan Tadic had a coin thrown at his head by a supporter outside its Philips Stadium home ground on Sunday.
Tadic, who scored an injury-time penalty in the 1-1 draw and clashed with PSV's Denzel Dumfries on the pitch, was targeted after the match as he walked to the team bus.
Three people have been arrested following the incident.
The club said it "regrets the incident" which "is not what PSV stands for".
A statement from the Dutch Eredivisie side said club security and stewards at the stadium worked with police to identify those who were arrested.
PSV's chief executive Toon Gerbrands has since spoken to his counterpart at Ajax, Edwin van der Sar - the former Manchester United, Fulham and Juventus goalkeeper - to apologise for "the way Dusan Tadic was treated".
"It does not fit the values of the club," PSV added in a statement.
"PSV will of course always keep in touch with various parties to guarantee the safety of visitors and players to the stadium."
Dutch football's governing body KNVB told BBC Sport it was aware of video footage of the incident, but added that no investigation had started as an official complaint had not yet been received.
The scenes outside the stadium followed a dramatic end to a tense draw which saw former Southampton winger Tadic rescue a point for the league leaders from the spot in the 92nd minute.
The Serb celebrated his goal in front of Dumfries who had conceded the penalty with a handball, and the pair were seen arguing on the pitch after the match.
Tadic told reporters that he was insulted and had his leadership questioned before taking the penalty, while Dumfries said the Ajax man "insulted his mother" in the verbal exchange.
The draw leaves Ajax six points clear at the top of the table, with PSV second.
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