Mamic is accused of abuse of power and graft that cost Dinamo more than 15 million euros and the state 1.5 million euros, with the cash allegedly embezzled through fictitious deals related to player transfers.
Lovren, 28, appeared as a witness to provide details on his 2010 transfer from Dinamo to French side Lyon.
But furious outbursts from Mamic during his questioning saw the defendant banned from future sessions in which evidence is presented.
The 58-year-old is being tried along with three others: his brother and former Dinamo Zagreb coach Zoran Mamic, former club director Damir Vrbanovic, and a tax inspector.
The Zagreb football club was supposed to receive nearly nine million euros for Lovren’s transfer to Lyon, but prosecutors say Dinamo paid nearly half of the money into Lovren’s account and he then transferred it to the Mamic brothers.
Lovren told the court that he had simply paid the money as a “loan” to Zoran Mamic and that most of it had since been returned to him, according to N1 television.
The courtroom, which has seen regular angry outbursts from Mamic since the trial opened in April, witnessed a similar incident on Friday.
Angered by a prosecutor’s questions to Lovren, Mamic started to shout and swear in the courtroom and accused the prosecutors of “manipulating the witness”.
“Would you like my blood, my liver? Shame on all of you,” he shouted before leaving the courtroom.
Judges then imposed the partial ban on Mamic attending further sessions.
Lovren had appeared at the court in the eastern city of Osijek in June but failed to testify as the trial was adjourned after another furious outburst from Mamic.
Real Madrid midfielder Luka Modric testified at the trial in mid-June but later faced questioning over alleged false testimony.
Mamic attended the trial on Friday on crutches after being shot in the leg by unknown perpetrators in Bosnia in August.
Dinamo Zagreb, where Mamic is currently a consultant, have called the injury an “assassination attempt”.
The trial is being held under strict security measures.
In July Mamic was separately charged, along with several others, of funnelling money from the club which allegedly cost it nearly 20 million euros.
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