Eduardo Vargas believes Chile's come-from-behind win over Panama on Tuesday will give them the confidence boost they need in their Copa America title defence.

Vargas scored twice in the first half to overturn an early deficit at the Centenario tournament, after Miguel Camargo gave Panama the lead in Philadelphia.

Arsenal star Alexis Sanchez scored a double of his own in the second half, either side of an Abdiel Arroyo header, to seal Chile's passage to the quarter-finals with a 4-2 win.

Vargas acknowledged Chile's performances have been severely lacking in quality compared to their 2015 title win, but believes the victory over Panama will provide the push they need.

"It's been a very important game not just for me but for the team as well," the 26-year-old Hoffenheim forward said.

"We are the champions of South America and we know we have not had the best games. We haven't shown the rhythm we had last year.

"But this gives us the confidence for what's coming up ahead. It gives us confidence to keep going and achieve our objective of becoming champions."