Holders Porto crashed out of the Europa League after a 4-0 thumping at Manchester City completed a 6-1 aggregate win for the English Premier League leaders on Wednesday.
Trailing 2-1 from the home leg, the Portuguese side's hopes of reaching the last 16 were dealt a crushing blow after 19 seconds at a sodden Etihad Stadium when Sergio Aguero fired City into the lead.
Aguero created a second for substitute Edin Dzeko after 76 minutes and Porto's night got even worse when Rolando was shown a second yellow card for voicing his opinion that Dzeko should have been ruled offside.
Late goals by David Silva and recent signing David Pizarro flattered Roberto Mancini's side who did not have things all their own way but had never looked in danger of losing.
The match was moved to Wednesday because Manchester United are in Europa League action in the city on Thursday against Ajax Amsterdam and it kicked off early so as not to clash with the evening's Champions League fixtures.
City will play Legia Warsaw or Sporting Lisbon, who meet on Thursday, in the last 16.