Lucas Viatri headed in two goals to help Boca Juniors to a 2-1 victory against Rafaela on Sunday and into first position in Argentina after five rounds of matches.
Colon looked set to take first place in Sunday*s late game, but German Pezzella equalized for Boca*s bitter rivals River Plate in the 89th minute to make the score 1-1.
In Sunday*s other games, Tigre and San Lorenzo drew 1-1 and Godoy Cruz defeated Independiente 2-1.
Viatri rose above the Rafaela defense to nod in the 70th and put Boca in the lead for the second time in the game, but goalkeeper Oscar Ustari was the hero for Boca after pulling off a short range save from Raul Ferro in second half injury time.
Sebastian Carrera had equalized for Rafaela in the 66th, after Viatri*s opener in the 25th.
The game was played at a neutral venue due to the closure, for one league game, of Boca*s Bombonera stadium after fans ripped down an advertising board close to the opposition bench during a Copa Sudamericana tie on Aug. 22.
Colon had looked dominant against River Plate, but Pezzella latched onto a precise throughball by Leonardo Ponzio and shot inside the near post to equalize.
Colon*s goal arrived in the 70th when Ruben Ramirez headed in from near the penalty spot following a left wing cross.
Tigre took the lead through Diego Castano in the 19th, but Luis Aguiar equalized five minutes later for San Lorenzo.
Castano was then sent off for Tigre in the 52nd and was followed in the 64th by San Lorenzo*s Franco Jara.
David Ramirez scored twice to help Godoy Cruz come from behind to win against Independiente.
Cristian Tula gave Independiente the lead before Ramirez equalized in the 45th and scored the second from the penalty spot in second half injury time.
In Saturday*s games, Ignacio Scocco scored the only goal in Newell*s 1-0 win against Estudiantes in the fourth minute of second half injury time, while Juan Pablo Caffa handed reigning champion Arsenal a 1-0 win over Lanus with a 47th minute goal.
An own goal by Sergio Rodriguez gave Velez a 2-1 victory against Belgrano. Fabian Cubero had opened the scoring for Velez, before Martin Zapata leveled the scores for Belgrano.
On Friday, Matias Donnet gave Union the lead in the 18th, but All Boys came back with goals from Martin Morel, Juan Pablo Rodriguez and Ivan Borghello to make it 3-1.
In games to be played Monday, Quilmes meet Argentinos Juniors and Racing plays San Martin.
