Pato - Horseball 

Diego de Torres Bello S.J. wrote accounts of traditional competitions held to celebrate St. Ignatius. 
June 16th, 1610: 

Artillery and musketeers have done their job, and some have left with pride to play ducks in front of our church.

Two groups of riders chased ducks in front of our church (it was in the middle of the present Plaza de Mayo)

Everyone was full of admiration, seeing them and horses that seemed tireless 

He indicated that indigenous riders were taking part in the game on April 4th, 1611 :

Cordova's parents encouraged Indians in the Calchaquí Valley to be rewarded so that they could throw arrows and run with ducks.

From  Félix De Azar's 1610 account of a corrida during the beatification ceremony of San Ignatius de Loyola in Buenos Aires:

Two teams of men on horseback get together and two far away destinations are indicated. Later on, they sew the leather where a live duck sticking its head out has been placed. This leather is made up of two or more handles from which the two strongest men in each team hold on to half way between the destinations that have been signalled. Enthusiastically, they pull strongly until the strongest team grabs the duck and carries it with them, thus making their rival fall down onto the floor if they do not let the duck go. The winning team starts running and the opponents race after them and surround them until reaching them through one of the handles. They pull strongly once again, and the team that manages to carry the duck to the stated destination wins