Argentina's Big Five prepare for clasicos
Estudiantes, coached by national team candidate Alex Sabella, are three points out in front with eight matches to go and a victory at the Amalfitani in the west of the capital would see pre-season favourites Velez drop six points behind them.
Arsenal are level with Velez and will remain in the hunt for the Apertura championship, the first of two in the season, if they win at home against Godoy Cruz, who for a majority of neutral observers are the best team in the country.
What Velez and Arsenal, with 23 points each from 11 matches, have and Estudiantes (26) do not, are strike duos who have scored most of their goals.
Estudiantes' strength lies in defence with only four conceded. Nine different players have scored their 15 goals while the Velez pair of Juan Manuel Martinez and Uruguayan Santiago Silva have seven each and are the championship's leading scorers.
"They are in good form, they've played together for some time. We'll have to be very concentrated because they won't forgive you for any errors," said Estudiantes centre back Leandro Desabato.
"It's obvious to anyone that we're missing a number nine," Desabato told reporters as Estudiantes have struggled to overcome the departure of Mauro Boselli, who top scored with 13 goals in the previous Clausura championship.
Arsenal's Mauro Obolo and Luciano Leguizamon have nine goals between them in their team's total of 13.
In the big derby in the capital, Huracan (10 points) are at home to "barrio" rivals San Lorenzo, who are the highest placed of the Big Five in fifth with 18 points, on Sunday.
The clasicos involving the other four major teams are a crossover between sides from Buenos Aires city and the suburb of Avellaneda.
Struggling Independiente (9) host Boca Juniors (16) at their Libertadores de America stadium in Avellaneda, while Racing Club (16) leave the suburb to travel into the capital to visit River Plate (17) on Saturday.
River and Boca are warming up for the "superclasico" at River's Monumental stadium in two weeks.