The 6-0 win over fellow Lisbon side Belenenses, had been followed up with a 2-0 win over Kazakhstan champions, Astana in the Champions League.
FC Porto also went into this game in reasonable form having beaten Arouca 3-1 in the league but having to settle for a 2-2 draw at Dynamo Kiev in the Champions League.
Sporting moved into second place behind FC Porto but left it late to beat 10-man Nacional.
The much-anticipated Clássico was seen as an early indication as to where the title might end up next May.
Benfica started the brighter of the two sides with Fulham loanee Kostas Mitroglou and skipper Luisão testing Casillas from corners. FC Porto appeared lethargic going forward and rarely troubled the Benfica back four.
Drama erupted just after the half-hour mark when former Benfica right-back, Maxi Pereira, saw yellow which lead to a melée between both sides.
Then on the stroke of half-time, Porto’s Maicon attempted a high clearance with a karate-style kick, just missing the head of Jonas. Referee Artur Dias blew instantly as both sets of players squared up to each other.
Meanwhile, Maicon was rushed from the scene and down the tunnel with haste.
The second-half saw a much stronger FC Porto performance with Aboubakar causing problems for Benfica. A superb cross by André André was met by the Cameroonian striker’s head. It beat Júlio César’s despairing dive only to rebound off the post and away to safety.
On the hour mark Aboubakar again tested the Benfica back four when he ran through on goal and evaded the challenge of Jardel, narrowly slipping the ball past Júlio César but sending it well wide of goal.
Sylvestre Varela replaced Jesús Corona with half-an-hour remaining and it was the former West Bromwich Albion loanee who made a key difference as his back heel teed up the on-rushing André André.
The former Vítoria de Guimarães midfielder calmly placed the ball past the diving Júlio César to give FC Porto a 1-0 lead, all three points and top spot in the Primeira Liga.
Sporting were quickest out of the starting blocks against Madeira side Nacional and had a strong claim for a penalty in the first minute but it was waved away by referee Fábio Veríssimo.
The visitors left themselves with a mountain to climb when Nuno Sequeira was given his matching orders just after the half-hour mark, accruing two yellow cards within the space of five minutes.
Despite having ten men for nearly an hour, Nacional held on and were on the verge of claiming a valuable point against Jorge Jesus’s side.
But with five minutes to go it was substitute Fredy Montero who snatched all three points for the Lions when he rifled a low shot into the far corner of the net. FC Porto and Sporting are four points clear of Benfica, SC Braga and Estoril on nine points.