RSL (3-3-1) got its third goal from Alvaro Saborio as it remained unbeaten at home and won for the second time in three games.
Both Beckerman and Olave scored on defensive miscues by the Union (1-0-5). Beckerman's tally in the 27th minute was set up when Union defender Cristian Arrieta made a bad pass to goalkeeper Chris Seitz and Saborio intercepted in the area.
Olave's marker in the 51st minute came after Seitz fumbled the ball in front of the goal.
RSL got the capper on a combination play from Saborio and Pablo Campos.