Victor Lindelof cancelled out Adrien Silva's early opener to help Benfica to a 1-1 draw with arch-rivals Sporting CP in Saturday's Primeira Liga encounter at Estadio Jose Alvalade.
Benfica knew they could not afford to lose with Porto hot on their heels in the race for the title, but their start did not offer any cause for optimism.
Goalkeeper Ederson fouled Sporting CP top scorer Bas Dost inside the area and Silva kept his cool from 12 yards, finding the bottom-left corner to open the scoring after just five minutes.
Dost then missed two chances to double his side's lead early in the second half, aiming a header over the crossbar before firing inches wide, and the Dutchman's failure to find the net would prove costly.
Referee Artur Soares Dias awarded Benfica a free-kick in a dangerous position in the 65th minute and Lindelof beat goalkeeper Rui Patricio with a sublime shot into the bottom corner to salvage a draw.
Benfica remain top of the table following this result with 72 points from 30 games, four clear of second-placed Porto, who have a game in hand. Sporting, meanwhile, occupy third place on 64 points.