Crowd trouble forced Benfica's Primeira Liga match at Academica Coimbra to be interrupted for five minutes late in the second half on Sunday, prompting the Lisbon club to protest at heavy-handed policing.
Play was halted when fans spilled onto the running track around the pitch to escape the trouble. Pictures showed smoke bombs and plastic seats being thrown as riot police entered the crowd wielding truncheons.
"Benfica regret and are puzzled by this aggression towards our fans," said the club in a statement. "During tonight's game, there was an indiscriminatory police action against the Benfica fans, including women and children."
"This police intervention followed an episode which happened before the match when our fans were banned from entering with scarves and flags bearing the colours and emblems of the club."
First-half goals by Nicolas Gaitan and defender Luisao gave Benfica a 2-0 win which kept the defending champions top with 28 points from 11 games, two ahead of Vitoria Guimaraes.
Third-placed Porto thumped Rio Ave 5-0 with all their goals coming in the second half.
Porto, playing in a fluorescent pink instead of their traditional blue and white stripes, broke the deadlock two minutes after halftime when Cristian Tello drilled an angled low shot past Cassio into the far corner.
Goalkeeper Cassio kept Rio Ave in the game until the 78th minute when Colombia striker Jackson Martinez broke from the halfway line, cut inside and fired a low shot just inside the post from outside the area for his eighth league goal of the season.
That was followed by a bizarre third goal in the 89th minute when Alex Sandro over-ran the ball but a defender's clearance struck him on the foot and flew over Cassio into the net.
Juan Quintero threaded the ball through for Oliver Torres to add the fourth and Danilo completed the rout with a thunderous left-foot strike.
