S.America Roundup: Fans fight on pitch in Uruguay
There was also a pitch invasion in Peru where Universitario supporters attempted to attack their own players after they conceded a late equaliser in a 1-1 draw at Atletico Minero
Danubio leap-frogged Nacional to go top of the championship's first stage after their 1-0 win but the match was overshadowed when fans fought on the field.
Shortly after the final whistle, dozens of visiting Nacional fans found their way through a hole in the fencing, invaded the pitch and managed to grab a Danubio flag.
This enraged the home supporters who also ran onto the field and a pitched battle ensued in which fans, some armed with iron bars, punched and aimed karate kicks at each other.
Media said that police took around 15 minutes to bring the situation under control.
A crowd of around 7,000 had packed into Danubio's tiny ground in the working-class neighbourhood of Jardines del Hipodromo.
Jorge Garcia headed the only goal in the second half from Sergio Leal's cross while Nacional had Adrian Romero sent off in the last minute.
Danubio lead with 24 points from 11 games, two ahead of Nacional and Cerro.
Around 100 Univeristario supporters ran onto the field and attempted to attack the players after the 1-1 draw away to Atletico Minero in Matucana. The fans also insulted the team and demanded the resignation of coach Ricardo Gareca.
The players left the field under police protection, went straight onto the team bus and headed for Lima, a journey of around four hours, without having a shower.
Roberto Jimenez put Universitario ahead but Jose Galvan snatched a late equaliser for lowly Atletico to the fury of the roughly 1,000 visiting supporters.
Sport Ancash's joy at being awarded the three points from their 1-0 defeat at home to Deportivo San Martin was short-lived as they lost 1-0 to Sporting Cristal.
Ancash were awarded a 3-0 walkover win last week because San Martin had arrived late for the game, a decision which left both teams level at the top of the championship's second stage with 40 points each.
San Martin went three points clear by winning 2-0 at Coronel Bolognesi with long-range goals from Ronald Quinteros and Jose Diaz.
Deportivo Pereira, with the eccentric Rene Higuita keeping goal at the age of 42, beat Bucaramanga 3-0 to qualify for the last eight of the Clausura championship.
Former Colombia goalkeeper Higuita, famous for his scorpion save against England at Wembley and a spectacular blunder in the 1990 World Cup against Cameroon, has made the latest of several comebacks at the provincial club.
Bogota pair Millonarios, who have won a record 13 titles, and Santa Fe both missed out.
Millonarios finished ninth, below Deportivo Cali on goal difference, despite beating Envigado 2-1 and Santa Fe lost 3-1 at Atletico Junior.
Cali went through despite a 1-0 defeat to La Equidad, who stayed one point ahead of Millonarios and also qualified. Deportes Tolima, Atletico Junior, Atletico Nacional, America, and Medellin were the other teams to qualify.
Three of the four Clausura championship quarter-final first leg ties ended in draws as Rangers held Universidad Catolica 3-3, O'Higgins and Palestino finished 2-2 and Colo Colo drew 1-1 at Huachipato.
Cobreloa, who backed down on their threat not to play Universidad de Chile in a row over the timing of the fixture, won 3-0 at home.
Deportivo Quito drew 1-1 at Barcelona to stay three points clear of their opponents at the top of the championship's final stage with four games to play.
David Quiroz put Barcelona ahead when his penalty hit the post but rebounded into the goal off Giovanny Ibarra in the 42nd minute.
Walter Calderon equalised in the 71st minute.
South American champions LDU beat Deportivo Cuenca 2-0 to go level with Barcelona.
Libertad stayed on course for a fourth successive title by winning 2-1 at Olimpia. Guarani, who won 3-1 at Sol de America, are three points behind.