Poland's Lechia Gdansk welcomed North Macedonia's Akademija Pandev for the opening leg of their first round Europa Conference League qualifier last Thursday night.
This was Lechia's first match in a European competition since their failed Europa League qualifying bid back in 2019.
However, the team's return to continental football was blemished by "unacceptable" scenes in the home stands.
Just seven minutes into the match, Belgium referee Nicolas Laforge was forced to stop play due to a brawl in the home section of the stadium.
The entire delay lasted for 30 minutes as the stadium announcer warned the crowd that if the violence didn't stop, the match would be abandoned and the visitors would receive an automatic walkover.
According to Polish news outlet Dziennik Baltycki, a pub outside the ground was also "demolished".
A statement from Lechia Gdansk said: "As we have seen, a group of hooligans interrupted the football spectacle for all the real fans in Gdansk. We would like to unequivocally condemn such behaviour. This is absolutely unacceptable for us.
"Our entire team, the club - many people have been working for many weeks so that today the fans can see from the stands the first match in several years and Lechia's victory in European cups.
"Unfortunately, instead of experiencing this meeting together with Lechia's fans, we witnessed unacceptable behaviour. We know that the authorities have already taken action, secured monitoring, and the first of the perpetrators have been identified and detained.
"The referee and delegate decided that the meeting would resume. We do not know what consequences this situation will end for the club.
"We are simply very sorry that a group of hooligans tried to ruin the match for almost 15,000 people in the stands. There is no and never will be consent to such behaviour at the Gdansk stadium!"
Lechia ended up winning the match 4-1 with Flavio Paixao scoring a hat-trick to give the Polish side the upper hand heading into the second leg.