Cristiano Ronaldo, Bernando Silva, Andre Silva and Nani all got on the scoresheet as the Euro 2016 winners finished top of Group A ahead of Mexico, who claimed the runners-up spot after registering a 2-1 triumph over hosts Russian Federation.
Zhirkov had almost opened the scoring for Russian Federation just a few minutes before the play that was reviewed, but his low left-foot shot went just wide.
"We are confident and we want to win in the last four".
It did not take long for the European champions to double their advantage through Bernando Silva, who confidently found the back of the net after receiving a pass inside the penalty box.
However, it was not all good news as Bernardo Silva went off injured at halftime, while a needless and reckless challenge from Pepe, with his side 2-0 up, earned the controversial central defender his second yellow card of the tournament, ruling him out of Wednesday's semi-final.
Forward Andre Silva wrapped up the comfortable victory with a fierce angled finish after 80 minutes and Nani added a fourth in stoppage time.
"We knew it could be complicated because we had seen New Zealand play Mexico and the problems they caused the Mexicans".
"We started the game really well, and were the stronger of the two teams".
Cristiano Ronaldo has urged Portugal to go all the way in the Confederations Cup after reaching the semi-finals of the competition.
Portugal is set to face the Group B runner-up on June 28, while Mexico will square off against the Group B victor on June 29.
Portugal ran away as the victors in the second half, with two more goals late on. "Life will go on, this is sport and I am convinced he will remain on the national team and make his fans happy".
Mexico were soon back on terms, though, with Araujo looping his close-range header over Igor Akinfeev in the 30th minute. "Every player and keeper is entitled to commit an error", Cherchesov said of the goalkeeping error.
Some talented youngsters have also been important for Portugal recently, giving hope that the team can continue to succeed even after the most experienced players begin being replaced in the not-so-distant future.