Spurs suffered their first defeat of the year on Thursday night, and one of Jose Mourinho's most-trusted generals was the catalyst for their downfall.

Defending champions Liverpool ran away with a 3-1 victory at the Tottenham Hotspur Stadium to bolster their title defence, while it leaves the north Londoners with plenty to do before they can truly be considered a contender.

It was a trio of errors that proved to be Spurs' Achilles' heel, all of which started with Eric Dier's ghastly judgement for Roberto Firmino's opener.

The £22.5m-rated star is above and beyond Mourinho's first-choice centre-back having started 18 of their 19 league outings, seven more than Toby Alderweireld, 12 more than Davinson Sanchez and 15 more than Joe Rodon, as per WhoScored.

As one of the regular starters, he should be a reliable figure in the heart of defence - that's why he's continually selected, right?

Well, his lapse in concentration to allow the Brazilian to ghost in and tap home right before half time to really set the tone for the rest of the game.

As Dan Kilpatrick wrote in his post-match ratings column for the Evening Standard: "It was another example of a big error undermining his performance," which echoed the thoughts of football.london reporter Alasdair Gold, who claimed Dier "makes some decisions that undo a lot" of his good work.

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Interestingly, both journalists graded Matt Doherty's display as worse than the Englishman, but that's a tad unfair. First of all, the 29-year-old was playing out of position at left wing-back and secondly, he had only just returned from injury.

The right-footed defender had missed their FA Cup win on Monday and their victory over Sheffield United in the league, so cut him some slack.

As mentioned above, Dier needed to do a lot better, especially considering his involvement in the match. He recorded the second-highest number of touches (91) but in doing so, delivered very little in return.

Indeed, the 43-cap England international lost possession 11 times as he was awfully careless in the passing game, also recording 11 missed passes and six missed long balls, via SofaScore.

Wasteful.

Firmino, who has struggled in front of the sticks this season, failing to score in the five league games before kickoff, had the better of Dier as he managed to fire off three shots, including the opener.

Doherty can be given a free ride this time around - it's the 27-year-old colossus who betrayed Mourinho.

Dier is one of the few defensive players the Spurs boss actually trusts, so it says a lot when Alderweireld didn't start, and they shipped three goals against a side who hadn't scored in the Premier League since December 27.

AND in other news, Spurs could find their next Danny Rose in £20m "special player"...