Porto defeated champions Benfica 2-0 in Saturday's Portuguese Super Cup to get one over their old rivals ahead of the new campaign.
Benfica finished eight points ahead of Porto last season but were defeated in the traditional season curtain-raiser.
Jorge Rolando scored after only four minutes and Radamel Falcao added a second after 64 minutes.
The goals ensured that the Portuguese Cup winners started the new season with an early trophy success.
It is the first piece of silverware for new coach Andre Villas-Boas, who was previously Jose Mourinho's assistant when Porto won the Champions League in 2004.