Two late goals saw San Lorenzo come from behind to beat the nine men of Rosario Central and move up to second in the early Clausura standings on Thursday.
The visitors had taken a fourth minute lead through Carlos Luna and looked like making it stand up, despite the 59th minute dismissal of Rafael Delgado.
But San Lorenzo finally found an equaliser through substitute Nicolas Blandi in the 85th minute, and three minutes later, he added a second to win it.
A miserable finish to the match for Rosario was completed by the 90th minute dismissal of Hernan Encina.
The win puts San Lorenzo second, one point behind Colon Santa Fe after six matches.
Quilmes moved off the bottom of the table with a 2-0 win away to Arsenal Sarandi thanks to a 23rd minute goal from Sebastian Martinez and a late strike from Sergio Hipperdinger.
Tigre and River Plate played out a goalless draw.