Buenos Aires, Argentina, Nov 21: Boca Juniors failed to seize on a two-man advantage as it was held to a 0-0 draw on Sunday by Buenos Aires rival Racing Club.
Boca leads the competition with 33 points from 15 matches, with Racing in second place on 25. Four matches remain and Boca could clinch the Apertura title in its next match, which is against Godoy Cruz.
Racing was reduced to 10 men after Agustin Pellettieri was sent off for his second booking in the 50th minute. Racing then went down to nine when Teofilo Gutierrez was red carded in the 77th.
In other matches Sunday, Union defeated San Lorenzo 1-0 and Colon defeated Rafaela 1-0.
The match at Boca's La Bombonera stadium started with a moment of silence for Dalma Salvadora Franco, the mother of Diego Maradona who died on Saturday in Buenos Aires of heart failure. She was 81, had been in poor health recently and had several stays in hospital.
The draw is unlikely to hurt Boca, which seems destined to win its 24th league title and its first since 2008.
In an open first half, both had scoring chances. Boca did most of the attacking and Racing replied on the counterattack.
Boca did little after Pellettieri was sent off with Racing often looking more dangerous. The few chances that Boca did mount were snuffed out by Racing goalkeeper Sebastian Saja, who came up with four or five key saves during the match.
Paulo Rosales scored in 73rd minute for Union in a 1-0 victory over San Lorenzo.
Esteban Fuertes scored in the 72nd for Colon in its victory.
On Friday, Tigre defeated Newell's 1-0 and San Martin and All Boys drew 0-0. In three Saturday matches, Argentinos Juniors beat Godoy Cruz 1-0, Independiente defeated Olimpo 3-0 and Velez beat Belgrano 3-1.
On Monday, Estudiantes takes on Banfield and Lanus plays Arsenal.