Leonardo Jardim's men are now 11 points clear of third-placed Porto with four matches remaining, although Luis Castro's side can cut that back to eight with a win against Academica in their game in hand on Sunday.
Midfielder William Carvalho enhanced his growing reputation with the game's opening goal in the 14th minute, the 21-year-old calmly firing his fourth league goal of the season past Matias Degra.
After Rui Patricio had saved well from Bebe, Sporting doubled their lead as Marcos Rojo applied a simple finish at the back post, capitalising on poor marking from the home side.
Bebe pulled a goal back for Pacos 10 minutes after the break, but just past the hour Adrien Silva restored Sporting's two-goal advantage with a thunderous strike from the edge of the penalty area.
The hosts then saw Filipe Anunciacao dismissed for a second booking, ending their hopes of mounting a comeback.
Elsewhere on Saturday, Sporting Braga's 2-0 victory left Olhanense bottom of the table.
Braga missed a first-half penalty through Raul Rusescu but he atoned by netting from the spot six minutes from time, with Brazilian Jander having been dismissed for the hosts.
Piqueti Silva completed the victory in stoppage time as he rounded Vid Belec before tapping into the empty net.
