Benfica saw its lead atop the Portuguese Liga reduced to two points this weekend as the club was held to a 1-1 draw at home by Estoril.
Second-place FC Porto secured a 3-1 win at Nacional on Saturday with all three goals being scored in the first 22 minutes for the defending champions, which put some pressure on Benfica ahead of Monday's clash.
And the home side fell behind to a goal from Estoril's Cafe in the 59th minute, while Maxi Pereira netted the equalizer nine minutes later.
But Benfica had to hold on for the final 12 minutes with 10 men as Carlos Martins was sent off after picking up his second yellow card.
With two games to play, Benfica holds a two-point edge on Porto, but the two sides will square off in Porto on Sunday in a potential title-deciding match.
A Benfica win will clinch the title for the Lisbon side, while Porto can take the lead with one match to play if the hosts snatch all three points.
Braga clinched a spot in the top four with a 3-2 win at Moreirense on Friday as Ze Luis scored the winning goal in the 83rd minute.
Pacos Ferreira stayed four points clear of Braga in third place after a 1-0 win over Sporting Lisbon on Sunday, Guimaraes downed Gil Vicente, 3-1, Academica used a goal from John Ogu in the 81st minute to top Setubal, 1-0, Olhanense won 1-0 on an own goal from Ricardo Monteiro of Rio Ave and Beira Mar used a pair of goals from Evanildon Gomes in a 4-2 triumph against Maritimo.