Leaders Racing notched their fifth straight victory to maintain their two-point lead at the top of the standings with one round remaining, while Olimpo continued their late drive up the table, stretching their unbeaten run to four matches.
A three-goal blitz over 14 minutes just before half-time saw Olimpo trump Godoy Cruz in Mendoza with Juan Ignacio Sills, Jonathan Blanco and Miguel Borja getting on the scoresheet.
In Monday's other match, Belgrano won 2-0 at Arsenal.
Sills gave Olimpo the lead in the 32nd minute, heading Leonardo Gil's corner inside the back post, while Blanco doubled the visitors' advantage from the spot four minutes later after Borja was tripped in the box.
Olimpo were cruising and struck another blow in the first minute of first-half stoppage time, with Borja playing a one-two with fellow Colombian Mauricio Cuero before poking his shot home.
While Godoy Cruz would finish the match with 15 shots compared to Olimpo's nine, the hosts could not convert any of their chances and their winless streak at home increased to four games.
Olimpo's victory took them above Rosario Central on goal difference to third-last - 18th - in the Primera Division with 18 points, while Godoy Cruz (21) slumped to 15th.
Racing Club helped Olimpo into 18th by crushing Rosario Central 3-0 on Sunday thanks to a brace from former Inter striker Diego Milito.
The win keeps Diego Cocca's men on top of the table with 38 points, two in front of River Plate, ahead of the final day of the season, while third-placed Lanus (34) dropped behind River with a 2-2 draw with Boca Juniors (31).
Fernando Cavenaghi struck twice as River came from behind to win 3-2 against Banfield on Sunday, while in Lanus the home side gave up a 2-0 half-time lead with Jonathan Calleri notching Boca's equaliser in the 88th minute.
With Lanus now out of the running for the title, River must win their last match of the campaign at bottom club Quilmes to claim the championship and hope Racing slip up when they host Godoy Cruz.
San Lorenzo claimed the biggest win of the round - crushing Estudiantes 4-0 - while Gimnasia La Plata defeated Quilmes 3-0 and Tigre overcame Atletico Rafaela 3-1.
In other results, Velez Sarsfield were too good for Defensa y Justicia 2-0 and Independiente prevailed 1-0 over Newell's Old Boys.
