Argentinos Juniors secured their second victory of the Argentinian Apertura season on Monday with a 1-0 triumph at Quilmes.
Leandro Barrera netted the game's only goal 16 minutes from time, capitalising on a mistake by home goalkeeper Emanuel Tripodi to lift the visitors into the top half of the table on seven points from five matches.
The result marked a first loss of the season for eighth-placed Quilmes, who stayed on eight points - four points behind leaders Boca Juniors.
Luciano Vietto netted a hat-trick as Racing Club climbed to second in the Argentinian Apertura standings with a 3-1 home win over bottom-of-the-table San Martin San Juan.
Vietto's 41st-minute opener was cancelled out by Claudio Riano three minutes after the interval, but the 18-year-old restored the hosts' lead on the hour and then put the result beyond doubt with a third goal 10 minutes later.
Racing goalkeeper Jorge De Olivera was sent off a minute from the end but there was not enough time for the visitors to make the most of their numerical supremacy.
The result lifted Racing within a point of leaders Boca Juniors and left San Martin San Juan still searching for their first point of the campaign.