The visitors have opened up a commanding lead at the top of the league table, currently 11 points clear of their opponents in second place with four games left to play in the season, meaning that a point or better in this match will guarantee them a first-placed finish come the end of July.
Match preview
While the odds are firmly stacked in favour of the visitors going on to lift the title, Ruben Insua will be hugely satisfied with his team's performance this season after finishing in sixth place last term.
They have taken 42 points from their 23 matches this season, which is just one shy of the tally they managed across the whole of last season, and they also hold the record for the fewest defeats in the league this season, with only three to date.
Los Santos's strength this season has unquestionably been their form at home, where they are unbeaten with a record of eight wins and four draws, and they are one of just two sides that are yet to taste defeat at home.
San Lorenzo have been the best defensive team in the league by some distance, with just nine goals conceded so far, and they have incredibly managed not to let in a single goal at home this entire season, keeping clean sheets in all 12 matches at Estadio Pedro Bidegain.
However, while there are several positives to take from the host's record this season, the one clear area of improvement they have is in the goal-scoring department, as their tally of 23 is the lowest among any of the top 10 sides in the current league standings.
Meanwhile, River Plate are on the verge of reclaiming the league crown after finishing third last term, and needing just one point from the final four matches; it is hard to make a case for them to be overtaken from here.
However, they will want to get the job done as soon as possible, and this would be the perfect time to do it against the number one contenders as it stands, while it would also lay down a marker for the second phase.
Martin Demichelis's side could have been home and dry already had they not lost 2-1 to Barracas Central last weekend, which brought an end to a five-match unbeaten streak that included four wins and a draw, though they did bounce back well to beat Colon 2-0 in midweek.
The major difference between River Plate and San Lorenzo this season has been their respective away forms, with the champions-elect currently boasting the best away record in the league of seven wins from 12, while their opponents have only managed three wins in 11 games.
While San Lorenzo's home record this season is formidable, it may not concern Demichelis too much as his side did beat Los Santos at this venue twice last year and are unbeaten against them in their last three encounters.
San Lorenzo Argentine Primera Division form:
L
D
D
D
W
D
San Lorenzo form (all competitions):
D
D
D
W
W
D
River Plate Argentine Primera Division form:
D
W
W
W
L
W
River Plate form (all competitions):
W
W
W
W
L
W
Team News
David Martinez and Bruno Zuculini have not made an appearance this season and will remain sidelined for the remainder of the campaign, while Pablo Solari could return to the starting 11 after serving his one-match ban for yellow card accumulation.
Matias Suarez and Leandro Gonzalez Pirez will be in the squad, but with limited match time in recent weeks and considering the importance of the match, the pair may have to settle for a watching brief this week.
Rafael Perez's sending-off against Racing Club means that he will not feature here, which will likely mean that Carlos Sanchez will return to the three-man defence alongside Gaston Hernandez and Gonzalo Lujan.
Augusto Batalla, Jalil Elias and Nahuel Barrios are all carrying four yellow cards each into the match and will miss the trip to Belgrano next week if they receive another caution in this one.
San Lorenzo possible starting lineup:
Batalla; Hernandez, Melli, Sanchez; Giay, Elias, Maroni, Braida; Leguizamon, Bareiro, Barrios
River Plate possible starting lineup:
Armani; Casco, Pirez, Diaz, Rojas; Aliendro, Perez, Fernandez, Barco; Beltran, Borja