Benfica kept the pressure on Liga leaders Braga with a 3-1 victory over Guimaraes at the Estadio da Luz on Saturday.
Braga beat Sporting Lisbon 1-0 on Friday night but Jorge Jesus' team joined them on 42 points. However, Braga remain top because of their superior head-to-head record against Benfica this season.
Argentinian forward Pablo Aimar gave Benfica a 17th-minute lead but Guimaraes went in level at the break thanks to Nuno Assis' goal a quarter of an hour later. Benfica secured their fourth straight league win though with a second-half brace from Carlos Martins (50 and 60).
Reigning champions Porto are six points behind the leading duo after a 4-0 win away to Nacional. The hosts had Alex Bruno sent off in the 29th minute and Varela immediately put Porto in front from the penalty spot. Colombian forward Radamel Falcao but the match beyond doubt with a goal either side of half-time and Varela rounded off the scoring five minutes from time.
Uniao Leiria moved up to fifth, one point behind Sporting Lisbon, with a 2-0 home win over Olhanense secured by goals from Silas (61) and Vitor Moreno (89).
Naval halted a run of three straight league defeats by beating Belenenses 1-0 as Nicolas Godemeche got the only goal.