Riquelme return no help as Boca suffer shock loss

City rivals River Plate lost 2-0 against San Lorenzo, also Sunday, as Lanus held onto the lead in Argentina's first division after a 0-0 draw with Racing.

In other Sunday games in Argentina, Godoy Cruz drew 0-0 with Argentinos Juniors and Tigre defeated All Boys 2-1.

Riquelme made little impact in his comeback after eight months of retirement and Damian Lizio put Union ahead against Boca in the 26th minute, chipping the ball over goalkeeper Agustin Orion from the edge of the six-yard area.

Bruno Bianchi doubled Union's lead with a strike from inside the penalty area in the 34th minute and Pablo Magnin added a third in the 51st minute by turning in the rebound after Andres Franzoia struck the post.

Uruguayan forward Santiago Silva headed home to claim a consolation goal for Boca in the 89th minute.

River Plate had won all three of its games under returning manager Ramon Diaz, but fell behind against San Lorenzo after 41 seconds when Denis Stracqualursi rifled in a shot following a scramble in the penalty area.

Mauro Cetto headed in San Lorenzo's second in the 20th minute to wrap up the scoring.

Lanus' perfect start to the season also came to an end but the team has yet to concede in four games and the goalless draw with Racing left it one point above River Plate.