|Fans in the 60,000 plus crowd at the Monumental were enraged, throwing objects on to the pitch [GALLO/GETTY]
Legendary club River Plate were relegated to the Argentine second division for the first time in their 110-year history on Sunday, sparking street battles between police and fans just outside its Monumental stadium.
The drop came after a 1-1 draw with Belgrano in the second leg of a demotion play-off. Mariano Pavone scored in the sixth minute for River, and Guillermo Farre equalised in the 62nd.
Belgrano won the first leg 2-0 on Wednesday. The game was suspended for 20 minutes when River Plate hooligans raced onto the field to taunt their own players.
Officials also stopped Sunday's match with about a minute to play, with police forced to turn fire hoses on River Plate fans who had begun to throw objects on the field.
As the fans were pounded with water, River Plate's players huddled on the pitch, many in tears, including goalkeeper Juan Pablo Carrizo.
Fearing violence, Argentine authorities deployed about 2,200 police - reported to be the largest security operation for a football match - to control the crowd at River Plate's stadium.
Police used water cannons outside the stadium immediately after the match, hoping to disperse quickly. Fans who poured out of the stadium faced police with batons and shields at every exit, while attack dogs and helicopters were reportedly on standby.
The area outside the stadium, located in a leafy northern suburb, looked like a war zone with police battling hand to hand with hooligans. Police fired rubber bullets and tear gas, and brought in mounted units to try to keep order.
Young, angry fans responded by throwing rocks at police, setting fire to rubbish bins and ripping down metal street barriers. Smoke was also seen billowing from one end of the stadium, with a half dozen ambulances seen entering the area about 45 minutes after the match ended. One policeman has reportedly been injured.
Suggestions to play the match in an empty stadium were turned down by interior ministry officials after consulting with the Argentine Football Association and its president Julio Grondona.
River, which would have stayed up had they tied with Belgrano on aggregate, had three or four chances in the first half but failed to convert.
In the second, with the match level at 1-1, Pavone missed a penalty by shooting directly at goalkeeper Juan Carlos Olave.
Just before River led through Pavone's goal, Belgrano looked to have scored but the goal was disallowed for offside. TV replays seemed to show it was a correct call.
Farre's equaliser came from 12 yards after two River Plate defenders had failed to clear the ball.
The demotion is humiliating for a club that has won more league titles than any team - 33 - and is known affectionately as "The Millionaires."