Sporting extended their unbeaten run to six games courtesy of a fourth victory in a row, but Marco Silva's men had to be patient and were dealt a blow when they lost on-loan Manchester United winger Nani to injury in the first half.
When the breakthrough did come it was Andre Carrillo who found a way past goalkeeper Mamadou Ba after 54 minutes for his first goal in over two months.
Carlos Mane doubled his side's lead barely two minutes later and doubled his account for the Primeira Liga season in the process.
Carrillo had an effort ruled out for offside before Joao Mario made it 3-0 with nine minutes remaining.
Jonathan Silva scored an 87th-minute own goal to deny Sporting back-to-back cleansheets, but nevertheless Silva's side head into Wednesday's make-or-break UEFA Champions League clash with Chelsea buoyed by another win.
Sporting are fourth in the standings, five points adrift of leaders Benfica, while Boavista are 13th.
