After a year-long break, the footballers became Portuguese champions for the 21st time in the club's history.
"Porto" managed to do this two rounds before the end of the championship - on Saturday evening they defeated the "Penafiel" footballers, who are falling into a lower league, with a minimal result. The only goal of the match was scored by the Brazilian Adriano from the penalty spot at the beginning of the second half.
With two rounds left until the end of the championship, "Porto" has a nine-point lead over the Lisbon "Sporting" footballers, who sit in second place. They played a goalless draw on Sunday with another team potentially falling into a lower league - "Naval".
This year, "Porto" can achieve a "double" if they defeat the financially troubled "Vitoria Setubal" team in the Portuguese Cup final on May 14.
The defending champions, Lisbon's "Benfica", who also played a draw on Sunday with the sixth-placed "Nacional", are two points behind "Sporting". These teams will fight for second place, which gives them the right to play in the third round of the UEFA Champions League qualifiers.
With about three minutes left until the end of the match against "Penafiel", "Porto" fans ran onto the field to celebrate the title. The match was stopped for 15 minutes, but the referee agreed to continue the game. There were no reports of incidents or arrests.
"We deserve the title of champions," said coach Co Adriaanse after a great series of eight consecutive victories that led to winning the championship.
"C. Adriaanse's merits are enormous," said "Porto" president Jorge Nuno Pinto da Costa after the match, adding that the 58-year-old Dutchman will remain at the helm of the club next year.
The former AZ Alkmaar coach took over at "Porto" in the summer when the club finished second in the Portuguese championship after two consecutive titles with Jose Mourinho.
During the season, C. Adriaanse received a lot of criticism for allowing Jorge Costa and Nuno Valente to leave the team - players who were leaders of the team that won the UEFA Champions League in 2004 - and for constantly changing tactics.