Nigerian left-back Zaidu Sanusi scored in extra time as Porto won their 30th Portuguese league title with a 1-0 victory against Benfica on Saturday.
With one round of games remaining, Zaidu scored on a counter-attack minutes into stoppage time to put Porto nine points ahead.
The outcome ensures that Sporting will finish second and qualify for the Champions League group stage, with Benfica finishing third.
Sporting also defeated Portimonense 3 goals to 2 on Saturday night and now leads Lisbon rivals Benfica by eleven points with a game in hand.
Benfica, who reached the Champions League quarter-finals this season, will enter the competition’s qualifying phase.
Porto set a new Portuguese league undefeated record of 58 games until their first league defeat this season, against Braga two weeks ago, under coach Sergio Conceicao.
Porto will have the opportunity to complete a season sweep when they meet Tondela in the Portuguese Cup final on May 22.