FC Porto fell five points back of league- 1 defeat at Gil Vicente.
The home side brought a five-match winless streak into the contest against the defending champions, but jumped out to a 2-0 lead at halftime after a first- half brace from Claudio.
Cunha scored early in the second half for Gil Vicente to make it 3-0 to the home side, while Porto could only pull one goal back through Varela 15 minutes from time.
The result allowed Benfica to go five points clear after a 2-1 win at Feirense on Saturday that saw Oscar Cardozo score the winning goal from the penalty spot in the 73rd minute.
Braga entered the weekend in third place and moved to within three points of Porto after a 2-1 comeback win at Maritimo on Monday as Nuno Gomes scored the winning goal 15 minutes from time.
Sporting Lisbon remained in the top four as American Oguchi Onyewu scored both goals in a 2-0 victory against Beira Mar, while Olhanense came from two goals down against Setubal to snatch a 3-2 win, with two goals coming from Jean-Paul Yontcha.
The weekend began with Guimaraes topping Nacional, 1-0, as Edgar's 78th-minute penalty kick proved to be the difference.
The other match on Saturday saw Rio Ave and Academica play to a 0-0 draw, while Sunday's action included a 4-2 win for Pacos Ferreira at Uniao Leiria as both Manuel Jose Vieira and Michel each scored two goals apiece.