The Saints, no doubt calling on their best known fan Pope Francis to say a prayer for them, must beat the Brazilian side at the Nuevo Gasometro (2300 GMT) to go through to the last 16 in the Libertadores Cup.
They are bottom of Group Two after conceding a penalty in the fifth minute of added time away to Ecuador’s Independiente del Valle for a 1-1 draw two weeks ago.
San Lorenzo’s protests against Paraguayan referee Carlos Amarilla over the penalty earned key midfielder Leandro “Pipi” Romagnoli and centre back Fabricio Fontanini four-match bans which South American governing body CONMEBOL handed down on Monday.
“With the match over, some San Lorenzo players and auxiliaries came on to the pitch to insult us, saying we are thieves, we stole the match from them,” Amarilla said in his match report publicised by Argentine media.
Amarilla added that only the quick intervention of police prevented him and his linesmen from being attacked on the pitch.
San Lorenzo, the only member of Argentina’s Big Five clubs never to have won the Libertadores Cup and desperate to make amends this year, also conceded a late equaliser in a 1-1 draw at home to group leaders Union Espanola last month.
The Chilean side secured their last-16 berth upsetting Botafogo 1-0 at the Maracana in Rio de Janeiro last week.
San Lorenzo can take heart, however, from their recent results in the Argentine “Final” championship where they appear to have reversed a habit of conceding late goals and turned the tables at the right moment.
Winners of the Inicial championship in December, they went top of the Final standings on Sunday with their second successive win, coming from a goal down to beat All Boys 2-1 with two goals in the final seven minutes.
The league match before last, they drew 2-2 at Tigre with an equaliser three minutes into added time.
“Every match we play now is a final for us. We have another on Wednesday,” coach Edgardo Bauza told reporters.
“The players are euphoric, I’ve calmed them because we don’t have time to celebrate,” he said after Saturday’s win.
Other teams to have reached the last 16 before this week’s final round of group matches include Ronaldinho’s holders Atletico Mineiro, fellow Brazilians and twice winners Gremio and 1994 champions Velez Sarsfield of Argentina.
(Editing by Pritha Sarkar)