Alfie Mawson's opportunistic strike hands Swansea crucial points to dent Liverpool's top-four ambitions

Virgil van Dijk’s Premier League debut ended in a sobering defeat for the Dutchman who was meant to solve his club’s defensive frailties. The £75m defender was at fault when he failed to clear a corner that enabled Swansea’s Alfie Mawson to score the only goal of the game.

It was the kind of error Jurgen Klopp had grown accustomed to before their record signing arrived from Southampton – a cross into a central area which a shaky defence failed to deal with.

The result is a setback in Liverpool’s attempt to forge a gap between themselves and the other Champions League contenders, but for Swansea it could mean everything.

The Welsh club closed the gap to safety to just three points and with only one defeat in six games in all competitions under new manager Carlos Carvalhal, they could yet now find the momentum to escape relegation for a second successive season.

It was Van Dijk who created Liverpool’s first opportunity when his long ball found Sadio Mane in space but the striker was unable to bring the ball properly under control under pressure from Lukasz Fabianski.

The danger signs were there again in the 13th minute when a ball whipped in from the left by Andrew Robertson ricocheted around the Swansea goalmouth, only for Roberto Firmino to be penalised for hand ball.

Liverpool’s first real alarm came in the 17th minute when Joe Gomez over-committed trying to intercept and Jordan Ayew was set free by Sam Clucas. Ayew took the ball wide before cutting back along the goal-line to fire past Loris Karius, but the referee had rightly already correctly blown for a corner.

The pattern of Liverpool dominating possession with Swansea content to sit deep resumed and when they forced a corner of their own, Van Dijk came close to goal on his League debut with a glancing header than drifted just wide.

They had a better chance on the half hour when Van Dijk elegantly chipped the ball forward to Mohamed Salah, who volleyed first time from eight yards but uncharacteristically fired over the bar.

Just when it appeared that Liverpool would soon take the lead, the bottom-placed club exposed old failings in the middle of the Liverpool defence to take the lead against the run of play in the 41st minute.

A sweeping move ended with a deep cross from Martin Olsson and a nervy Van Dijk miscued a rushed clearance away for a corner. Liverpool dealt with that one, but conceded a second and from that kick the Swans took their unlikely lead through Alfie Mawson.

Clucas swung the ball in, Van Dijk’s poor header struck Federico Fernandez and Mawson showed impressive goalscoring instincts to sweep the ball past a stranded Karius for the defender’s third goal of the season.

Jurgen Klopp looked aghast with another soft goal conceded in the centre of his defence – a reminder of exactly the kind of faults that Van Dijk was supposed to remedy. But the home fans celebrated wildly as if they suddenly believed their long haul to climb out of the relegation zone might just have begun.

It was not just Klopp who appeared rattled as Liverpool pair Andrew Robertson and Joel Matip were shown yellow cards in quick succession. Robertson was booked for kicking out at Ayew as he lay over the ball after a foul and then Matip went into the book for scything down Lucas.

But there was still time before the break for Salah to serve the ball on a plate for Mane with the last move of the half, only for the striker to wastefully volley wide from a tight angle.

Liverpool pressed for an equaliser throughout the second half, but were either guilty of failing to take their opportunities, or else were denied by an inspired Fabianski.

The Polish keeper was alert and showed his shot-stopping ability with two superb saves. The first denied Salah when he tipped over the Egyptian’s free kick with acrobatic save on the hour mark.

ThenFabianski dived low to deny Liverpool substitute Danny Ings late on as Klopp’s side laid siege to the Swansea goal.

In the dying moments, Firmino hit the bar in a goalmouth scramble, but somehow Swansea clung on.