Messi trains alone ahead of Argentina's opener

Lionel Messi trained alone on Saturday as Argentina continued their preparations for their Copa America Centenario opener against Chile.

Albiceleste captain Messi had to be substituted after sustaining a knock to his back during his country's friendly against Honduras last week, sparking fears he may not be fit in time for Monday's re-run of the 2015 Copa final in Santa Clara.

Messi is back with Gerardo Martino's squad in California after returning to Barcelona to give evidence in a tax fraud trial against him and his father in midweek, but the Ballon d'Or holder was unable to train with his team-mates.

A statement on the Argentine Football Association's official website read: "Lionel Messi and Lucas Biglia trained separately, while Javier Pastore and Ezequiel Lavezzi participated in the group play with a ball and then practiced apart."

It remains to be seen whether Messi will take part in Sunday's final training session before the Chile match.