Guimaraes seized a memorable win thanks to a mix of hard work at the back and effectiveness up front while defeat for Benfica means they end the season without a trophy.
Late Guimaraes goals from Soudani and Ricardo prevented Benfica from finding some solace after losing the championship to Porto and the Europa League final to Chelsea in the space of just a few days.
The Lisbon club enjoyed most possession but Guimaraes almost went ahead in a quick counter before the half hour. Left back Addy failed to dink it over Benfica keeper Artur and hit the side net instead.
Just moments Guimaraes defender Kanu tried to clear in the box but his kick bounced off Gaitan and straight into the net. Keeper Douglas was left stranded.
Just when Benfica looked in control, the dismal story of their season continued when they conceded twice in the last 10 minutes.
First Algerian forward Soudani levelled after a poor clearance from Benfica keeper Artur and two minutes later Ricardo grabbed the winner with a long-distance shot.
"I don't know what happened in the last 10 minutes," said distraught Benfica midfielder Nemanja Matic."We surely deserved to win something this season."
Two weeks ago, Benfica lost both a decisive league match against Porto and their Europa League final with stoppage time goals.
"We made history. So many don't know Guimaraes, even some Portuguese don't understand what we are all about. Now, they will," Guimaraes coach Rui Vitoria said with tears of happiness in his eyes.
It was joy for the many thousands of Guimaraes fans too, who travelled more than 400 kms, as they celebrated in a sun-soaked afternoon at the Jamor stadium built in 1944.
They had failed to win the Cup in their last five finals and, in the last two years ago, were subject to an humiliating 6-2 defeat by Porto.
- Sports & Recreation