Unai Emery’s side defended resolutely for much of the game, managing to get to half-time goalless, but they were ultimately undone by some typically fast attacking from Jurgen Klopp’s team in the second half.
It was a tentative start from the home side, though Mane will have expected to do better with a header when found by a neat cross from Mohamed Salah early on with the Senegalese forward directing his effort wide.
Thiago Alcantara came as close as anyone to breaking the deadlock in the first half with a shot from almost 30 yards that crashed against the left-hand post, but the visitors did a good job of frustrating the Premier League side in the opening 45 minutes.
Champions League Semi-final: Liverpool beat Villarreal 2-0 HIGHLIGHTS
An electric beginning to the second half from Klopp’s side finally saw them take the lead in the 53rd minute, with Jordan Henderson’s cross from the right taking a fortunate deflection off the foot of Estupinan and flying past Rulli at his near post.
Another arrived just two minutes later as a good passing move ended with Salah sliding a ball through to Mane, who prodded under the goalkeeper to make it 2-0 to the Reds.
The Yellow Submarine avoided further damage but have it all to do when the two meet again in the second leg at the El Madrigal next Tuesday.
Thiago once again shines in the middle
The former Barcelona and Bayern Munich midfielder has been purring in Liverpool’s midfield in recent games, and he was on form again here as he helped to dissect a stubborn opposition.
Thiago completed 99 of 103 passes (96.1 per cent), enjoying a fantastic pass completion percentage in the opposition’s half of 94.1 from 68 attempts. He also made more interceptions than anyone (five) and gained possession 10 times in all.
Liverpool travel to Newcastle United on Saturday as they resume their title chase in the Premier League, while Villarreal are away to Deportivo Alaves on the same day.