Lyon boss Bruno Genesio admitted it was worrying to see crowd trouble mar their 2-1 Europa League quarter-final first-leg win over Beskitas.
Crowd disturbances at Parc OL saw projectiles thrown, fans spill onto the pitch and kick-off delayed by 45 minutes.
Once the game finally got under way, Ryan Babel gave the Turkish side a first-half lead.
Fans clash at Lyon vs Besiktas
However, Lyon responded dramatically late on, with Corentin Tolisso equalising seven minutes from time before veteran Jeremy Morel nabbed the winner.
"It is distressing to see such incidents," Genesio said of the off-field drama. "This is the reverse of what should happen.
"We are here to give pleasure to people and not to see that. You had to stay focused."
On the pitch Lyon ran out 2-1 winners but Genesio urged his players not to get carried away ahead of the second leg.
"We dominated in the first period, with a goal conceded from a set-piece," he added. "We were higher after the break and we were worried about our opponent.
"It's good to come back and win the match against a very good team.
"It's only half-time in this quarter-final. We will have to go to Istanbul with all our weapons, all our qualities."