Daniel Passarella, known as the “great captain” as a player, donned his track suit as he went shoulder to shoulder with his River Plate team preparing for the biggest match in the club’s 70 years of professional soccer on Sunday.

River have played and won South American and world club finals, been crowned Argentine league champions a record 33 times and provided more players to the Argentine national team than any other club.

On Sunday, though, they must beat modest Nacional B (second) division Belgrano by two goals in a playoff second leg (1810 GMT) that could end in a humiliating relegation, River’s first ever.

Passarella, former captain and coach and now club president, has been with the team at a retreat outside the capital since their return from Cordoba after losing the first leg of the relegation-promotion playoff 2-0 on Wednesday.

A small consolation is that a 2-0 win will be enough to save River because in the event of a draw on aggregate, the top flight side retain their status.

Passarella, a defender in one of the best ever River teams in the 1970s, has not pushed coach JJ Lopez to one side and instead has added his support in training, talking to the players and supervising a practice of free kicks.

As president for the last 18 months, he has blamed the previous eight-year administration for plunging River into crisis on and off the pitch and a massive debt estimated at $40 million would back up this claim.

So does River’s position in the two league championships this season, having finished fourth in the Apertura in December and sixth in the Clausura this month.

That they should be in such dire straits is due to poor results in the 2008/09 season in particular which have contributed to a low three-season points average used to measure relegation.

Security forces are bracing for a huge crowd on Sunday and a nasty reaction if River fail to survive the drop, which added to the dent in prestige would mean big financial losses.

Hundreds of River fans had to be dispersed by riot police using waters cannons when they tried to storm the Monumental on Thursday in a protests at the team’s poor performance in Cordoba.

PHOTO: Fans of Argentine River Plate soccer club try to storm into El Monumental stadium to demand the resignation of the president of the club Daniel Passarella, in Buenos Aires June 23, 2011. REUTERS/Alberto Raggio/DyN.