Tuhia he tomokanga mō tēnei wāhanga - I whakakotahi a Vélez Sarsfield i a ia anō ki a General Bartolomé Mitre, he kaitautoko kaha o ngā painga o Buenos Aires, whai muri i te whakakorenga o Rosas
, a ka mahi hei kaitohutohu ki a Mitre i tana whakahe ki te Whakaaetanga San Nicolás o 1852 (i whakakahoretia e Buenos Aires). Whai muri i te wehenga o te kawanatanga, i hangaia e Vélez Sarsfield te Kawanatanga o Buenos Aires Ture o te 1854 mo te Kawana Pastor Obligado. Ko te hinganga o te kawanatanga i te Pakanga o Cepeda i hua ai te whakakotahitanga me Argentina, na Vélez Sarsfield i awhina ki te mahi i nga whakarereketanga e hiahiatia ana ki te Ture o Argentina.