Lisbon:Ricardo Quaresma scored in the 42nd minute on Saturday to give FC Porto a 1-0 win over Benfica in the Portuguese league.
Quaresma took the ball past David Luiz and used the outside of his foot to score and inflict Benfica's first league defeat in a year.
The defending champions' victory before 60,116 at Benfica's Stadium of Light extended its lead in the standings to seven points.
Porto has 32 points. Benfica follows with 25, five ahead of Sporting Lisbon, Setubal and Guimaraes. Setubal drew 1-1 with Belenenses on Friday.
Benfica's American midfielder, Freddy Adu, appeared as a 78th-minute substitute to replace Nuno Gomes and he immediately forced Porto goalkeeper Helton into a diving save.
Three Porto supporters were arrested for throwing stones at Benfica fans outside the stadium, news agency Lusa reported.
On Sunday, Sporting hosts last-place Leiria. Also, it's; Amadora vs. Leixoes; Braga vs. Maritimo; Nacional vs. Boavista; and Naval vs. Pacos Ferreira.
On Monday, Guimaraes hosts Academica.