Hundreds of fans from Istanbul football club Fenerbahce have clashed with Turkish police and occupied the pitch after a title match.
The team's traditional rival, Galatasaray, won the Turkish league championship following Saturday's goalless derby.
Police used their shields to protect Galatasaray players on the pitch at Fenerbahce's Sukru Saracoglu stadium.
Officers used pepper spray to disperse fans as players fled to changing rooms.
The violence followed a tense game during which referee Cuneyt Cakir booked several players and issued red cards to one player from each team.
After the final whistle, fans broke plastic chairs and threw them at the police and Galatasaray players. Flares were also thrown.
Violence continued outside the stadium, with Fenerbahce fans pelting a police vehicle with stones.
Rioters overturned rubbish bins and smashed shop windows, leaving nearby streets littered with debris.
Fenerbahce fans in Istanbul's Kadikoy district also overturned two police vehicles and set them on fire.
While journalists, players and even policemen were said to have been affected by pepper spray, there were no reports of injuries.
However, elsewhere in the country a 29-year-old man wearing a Galatasaray shirt was attacked by Fenerbahce fans and stabbed in the abdomen, the state-run Anatolia agency said. The man was said to be in a stable condition.
Galatasaray ended the four-way title play-offs with 48 points, one ahead of Fenerbahce. Trabzonspor were third and Besiktas fourth.
Galatasaray, former Uefa Cup winners, are now level on 18 championships with Fenerbahce.
Their fans celebrated in Istanbul, dancing, lighting flares and waving flags.