Mason Mount’s clever turn and finish in the first half helped bring some welcome relief to Blues manager Thomas Tuchel after his side’s heavy defeat to West Brom on Saturday, which was followed by a training ground incident between team-mates Kepa Arrizabalaga and Antonio Rudiger.
Ben Chilwell added a late second after a mistake by Corona, moments after substitute Christian Pulisic had hit the bar.
Having conceded five goals against West Brom, Chelsea produced a dogged defensive performance to earn a seventh clean sheet in nine European games this season.
Skipper Cesar Azpilicueta’s vital block denied Corona before Edouard Mendy kept out Pepe’s header.
With both legs of this tie in Spain at Sevilla’s Ramon Sanchez Pizjuan Stadium because of coronavirus travel restrictions between Portugal and the UK, this was Porto’s ‘home’ game, meaning Chelsea’s two away goals put them in pole position before next Tuesday’s second leg.