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.
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.
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.
In other results, Velez Sarsfield were too good for Defensa y Justicia 2-0 and Independiente prevailed 1-0 over Newell's Old Boys.
