Porto dethroned Benfica as Primeira Liga champions after the latter played out a goalless draw with fellow Portuguese title rivals Sporting CP.
Benfica had won four successive league crowns but their dominance came to an end following Saturday's stalemate against Sporting as Porto were crowned champions without kicking a ball.
The draw in Lisbon – where Benfica hit the woodwork twice in the first half – left both teams four points adrift of Porto, due to play Feirense on Sunday, with one round remaining.
It capped a successful first season in charge for Porto head coach Sérgio Conceição, who delivered the Primeira Liga crown back to Estadio do Dragao for the first time since 2012-13.
Meanwhile in Russia, Lokomotiv Moscow sealed their first league title since 2004 with a 1-0 win over Zenit.
An 87th-minute goal from Portuguese forward Eder ensured Lokomotiv cannot be caught by Spartak Moscow, who are four points adrift heading into the final matchday.