Purchase tickets to see a game at Beira-Rio Stadium. If there's nothing scheduled while you're in the area, you might like to check if they give a tour of the grounds.
When you've spent a bit of time at this Santa Tereza sporting facility, why not check out Porto Alegre Public Market, Moinhos de Vento Park, and Sao Pedro Theater? They're not too far from Beira-Rio Stadium and also a favorite with many tourists.