The Reds didn’t ever look in any trouble in the first leg, the only danger to them that frustration grew as the Spanish side kept them at bay in the first-half.
But Jordan Henderson’s cross found the back of the net with the help of a deflection off Pervis Estunpinan and less than two minutes later, Sadio Mane had doubled the lead with a smart finish.
Villarreal will have home advantage in next week’s return fixture, but that looks unlikely to stop Liverpool sealing a third Champions League final appearance under Jurgen Klopp.
Unai Emery’s side made their intentions very clear inside two minutes, when goalkeeper Geronimo Rulli took 30 seconds over a goal-kick much to the outrage of the Kop behind him.
Liverpool’s first chance of the match fell to Sadio Mane when he got on the end of a cross from Mohamed Salah, but he was unable to direct his header with the ball slightly behind him.
Jordan Henderson’s cross nearly found a way in at the near post, before Luis Diaz had a couple of shots from range saved. Giovani Lo Celso, on loan from Tottenham, made a brilliant block to deny Salah and the Egyptian then shinned an effort over the bar from close range as Liverpool piled on the pressure.
They came closest to the opening goal a few minutes before the break when Thiago tried his luck from 30 yards, only to see his brilliant strike smack off the outside of the post.
Liverpool had the ball in the back of the net shortly into the second-half as Fabinho finished from close range, but the linesman’s flag quickly went up with Virgil van Dijk offside in the build-up.
A brilliant two-minute spell was all it took for the Reds to take complete control of the tie. The ball was worked out wide to Henderson as Liverpool found some rare space, his cross flicked off Estupinan and floated beyond the goalkeeper into the far corner.
Emery didn’t have time to consider a change of approach before the lead was swiftly doubled. There was nothing fortunate about this one, with Salah playing a great pass through to Mane and he poked the finish past Rulli at the near post.
It was very nearly three midway through the second-half, as Andy Robertson volleyed home from a brilliant Trent Alexander-Arnold cross, but once again the offside flag was swiftly up as he went to wheel away in celebration.
Villarreal didn’t threaten to find a way back into the match, managing just a single shot across the 90 minutes, and they’ll need to produce an almost miraculous comeback on home soil next Tuesday if they are to turn the tie around and reach the Champions League final.