Pacesetters Benfica, who lost at Rio Ave, remain nine points clear of their Lisbon rivals, but Marco Silva's men produced a professional display as Sporting look to put the top two under pressure going into the final eight league matches of the season.
Joao Mario opened the scoring at Estadio Jose Alvalade after 14 minutes, heading Andre Carrillo's sumptuous right-wing cross beyond Douglas Jesus in the visitors' goal, before Adrien Silva extended the lead with a penalty just after the half-hour mark.
Joao Mario then turned provider as Islam Slimani nodded Sporting into a three-goal lead on the stroke of half-time, before a second penalty of the day 15 minutes from time was converted by Nani.
Paulo Oliveira's 81st-minute red card for two bookings invited Guimaraes to pull one back a few moments after, but Kanu's goal proved to be nothing more than a consolation.
Belenenses were unable to make the most of fifth-placed Guimaraes' third successive defeat, as they were beaten 1-0 at Boavista to leave them four points behind in the scrap for UEFA Europa League places.
Towards the other end of the table, Arouca gave their survival hopes a boost as a 3-1 win over second-bottom Gil Vicente moved them four points clear of the drop zone, while the day's other encounter saw Moreirense and Maritimo play out a 1-1 draw.
