In front of a full house, it was Sporting who made a dramatic start after just three minutes, when Ederson miss controlled a Luisão back-pass giving hotshot Bas Dost the opportunity to pounce.
Ederson could only upend the Dutchman to concede a penalty.
Adrien Silva stepped up and calmly sent Ederson the wrong way. Thereafter, the first-half turned into a scrappy midfield battle with Benfica having the better of possession but struggling to break down the Sporting defence.
Just before the interval, Grimaldo nearly levelled matters for the visitors when his free-kick was well saved by Rui Patrício.
Sporting were much improved in the second-half and Bas Dost had two great chances to increase the lead.
With Benfica looking less likely to make inroads in the second-half, Rui Vitória brought on Raul Jimenez for the ineffectual Rafa Silva.
When Benfica did find the equaliser, it was well worth the wait for the Benfica fans. When Alan Ruiz conceded a free-kick outside the area, Victor Lindelöf stepped up and hammered a rocket of a shot that Rui Patrício could do nothing about. Benfica were more than happy to take a valuable point in their quest to retain the Primeira Liga title. FC Porto could have closed the gap on the leaders to one point with what would have normally been a routine home victory over mid-table CD Feirense, who had leaked goals in their last six outings.
This goalless result was Porto’s fourth draw in their last five games and leaves them four points adrift of top spot.
On Monday, the club’s ‘Dragões Diário’ criticised match officials, stating that throughout the season endless strong penalty appeals had been denied.
The editorial went on to say that in recent weeks, clear penalties had not been given against Rio Ave, Arouca and Feirense.