Boca Juniors ended 10 days of internal squabbling by beating arch-rivals River Plate 1-0 away in the biggest fixture of the Argentine season, despite playing most of the second half with 10 men.
|Riquelme was in commanding mood [EPA]
Lucas Viatri headed the only goal of El Clasico following a Juan Roman Riquelme free kick in the 61st minute, nine minutes after Hugo Ibarra was sent off for insulting a linesman over the award of a throw-in.
Both teams went into Sunday's match under pressure.
Defending champions River started the weekend in 18th place in the 20-team table, having won only one match out of nine in the championship.
Boca had lost three of their previous four games and were then hit by a public row after defender Julio Cesar Caceres gave a radio interview criticising Riquelme, who immediately hit back.
A peace agreement was settled on Friday after the Paraguay defender apologised.
Sections of the Argentine media had blamed Riquelme for the slump in the national team's form that leaves their World Cup qualifying hopes in peril and culminated in the resignation of Argentina coach Alfio Basile last week.
But the mercurial Riquelme answered his critics with an excellent performance as he controlled the Boca midfield.
River edged the first half, striker Radamel Falcao Garcia hitting the post with a shot which slipped through goalkeeper Javier Garcia's hands.
Boca dominated the second, squandering two chances on the break before Riquelme fired narrowly wide from the edge of the area.
Boca have 17 points from 10 games, eight behind leaders San Lorenzo who beat San Martin-Tucuman on Saturday.