After becoming something of a laughing stock for his performances at the start of his career on Merseyside, the Spaniard began to show considerable signs of improvement in his game.
At the start of this season, he was a permanent fixture in Jurgen Klopp's side, showing the sort of determination and defensive grit his earlier performances had been lacking.
However, West Bromwich Albion winger Matt Phillips caused the 25-year-old all sorts of problems - with the Reds allowing a two goal lead to slip at the Hawthorns.
Fans were quick to take to social media to slate his performance, and talkSPORT has compiled a few of the best (and worst) tweets for your viewing pleasure.