Benfica win derby to keep title race alive
Benfica moved to within eight points of undefeated Porto with 10 matches left in the season.
Salvio scored the opening goal after 15 minutes, pouncing on a poor clearance by Pedro Mendes to score with a diagonal right-foot shot from inside the box.
Benfica were reduced to 10 men when central defender Sidnei was dismissed for a second booking moments before halftime and Sporting created the first clear chances after the break.
Chilean playmaker Matias Fernandez broke into the box to force keeper Roberto into a fine reflex save on 53 minutes and Portugal striker Helder Postiga sent a looping header just wide five minutes later.
Against the run of play, Gaitan added Benfica's second in the 63rd minute with a half-volley that went in after a deflection off centre back Anderson Polga and the hosts never threatened to get back into the match.