Naby Keita’s drive deflected off Oliver Torres and looped into the net after just five minutes to give the Reds the perfect start.
Roberto Firmino then doubled the lead midway through the first half, turning in Trent Alexander-Arnold’s low cross from point-blank range to seal a 2-0 aggregate lead at the half-way stage.
The teams will meet again next Wednesday in Portugal to determine who set-ups a semi-final meeting with either Manchester United or FC Barcelona.
Team news
Liverpool made three changes from the team deployed at Southampton on Friday night as Dejan Lovren, James Milner and Jordan Henderson returned in place of Joel Matip, Georginio Wijnaldum and the suspended Andy Robertson.