Benfica won the Portuguese league for the second year running on Sunday with one game to spare when they drew 0-0 at Vitoria Guimaraes and rivals Porto were held 1-1 at Belenenses.
Porto were on course to take the title race to the final weekend when Colombia forward Jackson Martinez gave them a first-half lead, turning in a cross at the near post for his 21st goal of the season.
But their chances evaporated on a hot afternoon when Tiago Caeiro snatched an 85th minute equaliser, firing home from close range after Dalcio's pass opened up the Porto defence.
The results meant that Benfica, who have won 26 of their 33 games and lost only three, stayed three points clear of Porto with one match each to play and cannot be caught because they have the better head-to-head record.
Benfica won 2-0 at Porto in the first meeting and drew 0-0 in the return on their way to a record 34th league title, seven more than their old rivals.
It was the first time for 31 years that the Eagles have won two titles in a row and a remarkable achievement for coach Jorge Jesus, who had to rebuild his side after several key members of last season's treble-winning team were sold.
"Benfica were better than our rivals and that's why we reached the end in first place," said the fiery 60-year-old who has also led his side to two Europa League finals in six years in charge.
"With me, Benfica have always been challenging for or winning titles. We won this championship with the experience we gained over the last six seasons."
Benfica twice hit the woodwork in the first 20 minutes at Vitoria and dominated possession without creating many further chances.
News of Caeiro's goal set off celebrations among the Benfica fans at Vitoria, where their own team had become bogged down in a scrappy midfield battle.
The match was held up for two minutes in stoppage time when several flares were thrown onto the pitch from fans in the Benfica contingent behind the goal.
"It was a shame not to have won today, we played well. Vitoria had one chance and indulged in some gamesmanship which they did not need to do because they are a good team," said Jesus.
Asked if he would congratulate Benfica, Porto coach Julen Lopetegui told reporters: "I congratulate everyone who has contributed to Benfica winning the title."
