A 4-0 victory over River Plate at the Monumental on Wednesday without suspended midfielder Juan Sebastian Veron and in-form winger Enzo Perez kept Estudiantes two points clear of Velez Sarsfield, their only rivals for the title.
If Estudiantes, seeking their fifth domestic league title, draw with Arsenal and Velez beat Racing Club, the rivals would go into a play-off since goal difference is not taken into account.
Velez coach Ricardo Gareca, who steered his team to the Clausura title in the 2008/09 season, remained upbeat.
"Our faith is intact. The dream of being champions continues and it won't end until the championship is over," Velez told the sports daily Ole on Friday.
"Obviously, we know we have tough opponents (in Racing) but so do Estudiantes. Arsenal are the third best team in the championship, they're having a great campaign. We must win our match and hope."
REPEAT FEARS
Third-placed Arsenal will be no pushovers and Estudiantes will be wary of a repeat of last season's Clausura when they were held 0-0 at home in their penultimate match against Rosario Central, who were later relegated, and allowed Argentinos to pip them to the post.
Veron, who had reached five bookings in the 3-1 win over title holders Argentinos Juniors, is back for the decider, as is Perez who was sent off in a 2-1 away win over Independiente the weekend before last and suspended for two matches.
Velez, whose Uruguayan striker Santiago Silva is top scorer in the championship with 11 goals, will probably rue the day they were held 0-0 at home by Estudiantes.
They are away to much improved Racing, whose 1-1 draw away to Godoy Cruz in Mendoza was one of the best matches of the season and kept them in fourth place.
River are fifth equal with Godoy Cruz but their poor points average over three seasons means they are one place above the relegation zone with only the Clausura championship in the second half of the season left to ensure top flight survival.
River's caretaker coach JJ Lopez, in charge for five matches since Angel Cappa was sacked, has said that he would not continue at the helm after this championship.
Media speculated that Estudiantes coach Alex Sabella, who began his playing career alongside Lopez at River, was favourite to take over at the Monumental.
