Leading club River Plate was relegated to the Argentine second division for the first time in its 110-year history on Sunday, sparking ugly riots between police and fans with dozens injured inside and outside Monumental stadium. (Pics)
The relegation came after a 1-1 draw with Belgrano in the second leg after Belgrano had won the first leg 2-0 at home.
Violence broke a minute before the match was over. Angry fans pelted players with objects thrown from the stands and police replied with high-powered fire hoses with some fans climbing restraining fences topped with razor wire.
As fans were pounded with jets of water, River Plate's players huddled on the pitch, many in tears, including goalkeeper Juan Pablo Carrizo.
The mayhem quickly spread outside River's 50,000-seat stadium. Alberto Crescenti, head of emergency medical services, said at least 55 people had been injured.
Nilda Garre, the minister for security, said 35 police were injured.
"Fortunately, none have their lives at risk," the Argentine news agency DyN reported her saying.
Police used water cannons outside the stadium immediately after the match, hoping to disperse fans quickly. Fans who poured out of the stadium faced police with batons and shields at every exit, while attack dogs were ready and helicopters hovered over the stadium.
The area outside the stadium, located in the leafy northern suburb of Nunez, looked like a war zone with police battling hand to hand with River Plate hooligans, who are known by the colorful nickname "Los Borrachos del Tablon" - the Drunks in the Stands.
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 vehicles, and ripping down metal street barriers. Smoke was also seen billowing from one end of the stadium with reports that concession areas and other parts of the stadium had been set on fire.
Fans were also seen ripping up stadium seats and using them as weapons in fights inside the venue.
Half a half dozen ambulances entered the stadium area about 45 minutes after the match ended, with live television coverage showing medics working on the injured while street fights erupted just a few feet (meters) away.
As the troublemakers were driven away from the stadium, there were reports of stores and shops being broken into on one of Buenos Aires' most famous thoroughfares - Avenida Del Libertador.
Fearing this kind of violence, Argentine authorities deployed about 2,200 police - reported to be the largest security operation for a football match - to control the crowd.
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.
The violence was predicted. On Wednesday, the first leg in Corboda was stopped for 20 minutes early in the second half after River Plate hooligans ripped through a fence and raced across the field taunting and pushing River Plate players.
The ugly scenes, seen worldwide, came just days before Argentina hosted the Copa America - the continental championship for national teams - with the first match on Friday in La Plata, located about 60 kilometers (35 miles) southeast of Buenos Aires.
River Plate's stadium is scheduled to host the final on July 24, but that fixture is in doubt. Buenos Aires prosecutor Gustavo Galante said after the match he was moving to close the stadium for 30 days to investigate how many fans were allowed to enter the aging facility.
Football-related violence is endemic in Argentina, fallout from lax security, decrepit stadiums and hooligan groups that present a menace at almost every match. The nonprofit group "Let's Save Football" says 287 people have been killed in football-related violence dating from 1924, and 14 have died in the last 16 months.
River, which would have stayed up had it tied 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 equalizer came from 12 meters (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 "Los Millionarios."
River can return to the top flight after only one season in the second division - known as B Nacional - by finishing in the top four to be promoted automatically or via a playoff.
Relegation in Argentina is determined on results over three seasons, and River has been poor over that period. Faced with debts estimated at $19 million, it has sold off much of its top talent to European clubs, hoping to balance the books.