Belgrano defeated River Plate 2-0 Wednesday in the first leg of their relegation playoff, a match threatened with violence early in the second half when dozens of hooligan fans - at least one wearing a mask - ripped through a fence, raced across the pitch and taunted and shoved River Plate players.

Referee Nestor Pitana halted the match in Cordoba for 20 minutes as police with batons and shields cleared the troublemakers from the field and stands. The incident took place just a minute after Cesar Pereyra gave Belgrano a 2-0 lead in the 50th. Cesar Mansanelli scored Belgrano's first goal in the 26th.

The return match is scheduled for Sunday at River Plate's 50,000-seat stadium. The possibility of violence looms with River Plate facing relegation to the second division for the first time in its history.