Carlos Tevez scored twice in the final half hour as Boca Juniors came from 2-1 down to beat River Plate 4-2 at El Monumental in a thrilling Argentine 'superclasico' on Sunday.
The victory put Boca top of Primera A with 28 points from 13 matches, at least until Estudiantes (27) take on San Martin later.
With Boca trailing 2-1, Tevez took advantage of an error by young goalkeeper Augusto Batalla who came out of his box and missed his tackle on the striker in the 62nd minute.
The former Manchester United, Manchester City and Juventus striker then curled a superb shot into the top far corner in the 82nd minute before substitute Ricardo Centurion completed the victory in added time.
Tevez also laid on the opening goal, in one of the best superclasicos in recent memory, for Walter Bou in the 14th minute.
River though led at halftime after a brilliant volley from Sebastian Driussi, the championship's leading scorer with nine goals, in the 35th minute and a header by Lucas Alario five minutes later.
San Lorenzo are third on 27 points after a 3-2 home win over Union on Saturday. River are 10th with 19 points.