River Plate's title challenge took a hit on Sunday as the club needed to come from two goals down to claim a 2-2 draw at Union.
Union entered the match just five points above last place, but the hosts took a 2-0 lead in the first 35 minutes with goals from Andres Franzoia and Juan Cavallaro.
Rogelio Mori began the comeback for River by scoring in the 37th and Franzoia failed to convert a penalty kick shortly before halftime which would have restored Union's two-goal advantage.
Rodrigo Mora then netted the equalizer seven minutes from time for River, which remains in the top three.
Newell's is also in the title mix and the club dropped points at Quilmes on Saturday after being held to a 1-1 draw.
Ignacio Scocco scored after eight minutes, but he missed a penalty kick later in the half, opening the door for Miguel Caneo to net the equalizer in the 86th minute for Quilmes.
Arsenal secured a 1-0 win over Racing in the lone match on Friday with a goal from Nicolas Aguirre.
Boca Juniors won for just the second time in 14 league matches as Juan Martinez scored early in the first half of a 1-0 Boca win against Colon, Godoy Cruz scored three goals in a 13-minute span to top Velez Sarsfield, 3-1, and Estudiantes toppled Atletico Rafaela, 2-0, despite playing the entire second half with 10 men.
Juan Caicedo's brace allowed Independiente to down San Martin, 3-1, San Lorenzo beat All Boys, 3-0, with two goals from Ignacio Piatti and on Monday, Belgrano picked up a 3-1 victory at Argentinos Juniors while Tigres was held to a 0-0 home draw by Lanus.