San Lorenzo failed to seal the Argentina Primera Division title after a 0-0 draw against Estudiantes on Sunday.
With Lanus draw 2-2 against Boca Juniors, San Lorenzo would have sealed top spot if they had claimed a home win.
The league leaders visit third-placed Velez Sarsfield on the final day as they aim for their first title since 2007.
Lanus missed the chance to draw level on points with San Lorenzo after twice giving away a lead at home to Boca.
Marcos Astina gave Lanus the ideal start with his goal midway through the first half as he placed an Oscar Benitez pass into the bottom corner.
Boca left-back Emanuel Insua set up the 51st-minute equaliser as Nicolas Blandi put away his cross.
Lanus midfielder Jorge Ortiz was sent off just moments later after a late challenge saw him pick up a second yellow card.
The hosts were lucky to get their third as Boca goalkeeper Agustin Orion tried to play out from defence and turned the ball over.
Jorge Pereyra crossed from the right and Benitez was on hand to poke into an empty net on 62 minutes.
Lanus' lead only lasted three minutes before Juan Sanchez Mino's low strike from inside the area beat Agustin Marchesin.
Matias Martinez was shown a straight red card for Lanus eight minutes before full-time after appearing to accidentally kick an opponent in the head.
Velez Sarsfield and Newell's Old Boys also remain in the title race.
A 2-0 win at Colon helped Velez move to within two points of top while Newell's Old Boys' poor form continued with a 3-1 loss at All Boys, but they are the same margin off first place.
Belgrano handed Arsenal a 4-1 thrashing, Tigre overcame Atletico Rafaela 3-1 and River Plate edged Argentinos Juniors 1-0.
Gimnasia La Plata claimed a thrilling 3-2 win over Quilmes, Godoy Cruz were beaten 1-0 by Olimpo while Rosario Central and Racing Club drew 1-1.
|25||P. Alvarado||64' 90'|
for L. Romagnoli 62'
for E. Kalinski 72'
for H. Villalba 82'
|Klose lauds Ronaldo after scooping record|
|Iran refute Susic claims|
|Fernandez named Deportivo boss|
|Argentina have no chance, says Robben|
|Hierro to replace Zidane as Real first-team coach|
|Rhodes signs new Rovers deal|
|Arsenal complete Sanchez swoop|
|Inzaghi backs under-fire Balotelli|
|Defeat has overshadowed display - Vlaar|
|Maradona: Germany full of themselves|
|Barry hoping for England recall|
|Green extends QPR stay|
|Shanghai Shenhua 1 Guangzhou Evergrande 2: Rong leaves it late in dramatic win|
|Germany hope for Brazilian support|
|Torino striker Cerci in demand|
|FIFA critcised following Mascherano incident|
|Bernat happy at Bayern despite bad memories|
|Giggs backs Van Gaal to thrive at Old Trafford|
|Tadic can fill Lallana void - Koeman|
|New five-year deal for Nasri|
|Barcelona release injury-hit Cuenca|
|Suarez appeal rejected|
|La Decima a reflection of Di Stefano - Perez|
|Buoyant Mazzarri eager for Inter success|
|Mandzukic joins Atletico|
|Van Gaal criticises third-place play-off|
|Halilhodzic yet to decide future|
|Mandzukic eager for Simeone link-up|
|Davies hoping for Hull deal|
|Poyet hopeful over Altidore fitness|
|Diego close to ´dream´ Fenerbahce move|
|Inter loan out youngsters|
|Fired-up Cole can inspire Villa, claims Lambert|
|Hughes hailed for winning over Brit doubters|
|Hajrovic signs for Bremen|
|Hull can buck Europa League trend, says Meyler|
|Mertesacker talks up German chances|
|Swansea reveal Tottenham contact over Davies, Sigurdsson|
|Lloris pens five-year deal at Tottenham|
|Fernandinho: ´The pain is big´|
|MLS Preview: Portland aim for swift revenge against Seattle|
|Sabella: Germany have an advantage|
|Second Argentine journalist dies in Brazil|
|Aguero: Argentina defied critics|
|Impressive Mascherano thrilled with final´s berth|
|Zuniga offered protection by Colombia|
|Germany vowed not to ´humiliate´ Brazil|
|Hong resigns from South Korea post|
|Third-choice Vlaar ´wasn´t nervous´|
|Van Gaal: I wanted Krul in the shootout|
|Argentina: Key factors in reaching the final|
|Sabella revels in semi-final win|
|Proud Robben feels pain of World Cup exit|
|FIFA World Cup: Netherlands 0 Argentina 0 (after extra time, 2-4 on penalties)|
|Susic signs two-year extension with Bosnia-Herzegovina|
|Hummels in race to make World Cup final|
|Scolari still baffled by Brazil collapse|
|Spendlhofer and Benedetti leave Inter|
|Neymar ´recovering well´ from injury|
|Villarreal sign Jonathan dos Santos|
|Arteta happy at Arsenal, insists agent|
|Birsa makes Chievo loan switch|
|FIFA suspends Nigeria over political interference|
|Di Stefano funeral held in Madrid|
|Hangeland scathing of ´difficult´ Magath|
|Thiago Silva in fan plea|
|Isgrove earns fresh one-year deal at Southampton|
|Morata edges closer to Juve switch|
|Nugent pens two-year extension at Leicester|
|Gomez delight with ´perfect´ Germany|
|Costa Rica to discuss Pinto future|
|Arfield agrees Burnley extension|
|Allardyce targets four more signings|
|K.League Review: Jeonnam close gap on Pohang, Jeonbuk|
|Maradona: Thrashing damages Brazil´s image|
|Kasami makes Olympiacos move|
|Chelsea complete Pasalic signing|
|Helenius makes temporary Aalborg return|
|Higuain set for Napoli stay|
|Basta targets return to Europe with Lazio|
|Lewandowski willing to adapt for Bayern|
|New Hull deal for Jakupovic|
|Atletico agree Mandzukic deal, claims Sammer|
|Fulham seal Stafylidis loan|
|Alves pens new Valencia deal|
|Ochoa to take time over future|
|Brown could miss three months|
|Adams: Norwich will not overspend|
|Gundogan unsure when rehab can step up|
|Stoke chairman wants long Begovic stay|
|Brazilian media reacts to semi-final exit|
|Icardi vows to remain at Inter|
|Robben is player of the World Cup, says Kluivert|
|Klose focused on final after breaking record|
|Prandelli takes aim at Balotelli, Rossi|
|Schweinsteiger sorry for Brazil battering|
|Brazil scarred for life, says Fred|
|Sabella: Argentina ´have already won´|
|Muller stunned by rout|
|Low lauds ice-cool Germany|
|Tearful Luiz apologizes for semi-final loss|
|Scolari sorry for ´catastrophic´ Brazil hammering|
|Brazil join sport´s biggest chokers|
|Reality kills Brazilian dream on a surreal night|
|FIFA World Cup: Brazil 1 Germany 7|