The Swedes scored three times in the first half to eliminate Portugal from the tournament.
The team ranked second in the world proved to be too strong for their opponents and will return to Leigh Sports Village next Friday to face one of the other countries.
Filippa Angeldal scored the first goal of the tournament after a weak clearance by Portugal keeper Morais.
Angeldal doubled the lead with a first-time shot after another set-piece, and it was three deep into the first half when Costa headed into her own net.
Stina Blackstenius added the fifth goal as Sweden produced a statement win going into the knockout stage.
After losing to Russia in the play-offs, Portugal secured a place in the tournament, even though Russia were kicked out of the tournament.
After their biggest win in England this summer, Sweden march on despite being the second lowest ranked team at Euro 2022.
The Netherlands had played out a draw with Sweden in their first game. The Dutch beat Switzerland to finish with seven points, but the Swedes thrashed Portugal to top Group C.
The runners-up at last year's Olympics came from behind to beat Switzerland.
Catarina Amado was carried off on a stretcher in the first half as Portugal suffered in the heat.
Before the match, the Swedes were dealt a blow when Seger wasn't ready to start.
Since 2005, she had missed a match at the European Women's Championship.
But Sweden overcame her absence to produce an impressive performance that suggests they mean serious business, and they celebrated a fine victory at the end of the game.