Croatian attacker Orsic, 26, notched his treble in Dinamo Zagreb’s 4-0 home win over Atalanta on Wednesday.
The result put Dinamo top of Group C, which also contains Shakhtar Donetsk and Manchester City.
Orsic’s exploits followed 19-year-old Salzburg striker Haaland netting three times in a 6-2 victory over Belgian side Genk on Tuesday.
Salzburg are top of Group E ahead of Napoli and Liverpool.
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