MANCHESTER (AFP) - Liverpool inflicted a historic hammering on Manchester United as Mohamed Salah scored a hat-trick in a 5-0 win at Old Trafford on Sunday (Oct 24), leaving Ole Gunnar Solskjaer clinging to his job.

For the first time in Premier League history, United trailed 4-0 at half-time and failed to score in a hopelessly one-sided contest. The Red Devils have now taken a run of one point from a possible 12 in the league.

Naby Keita started the rout before Diogo Jota doubled Liverpool's lead inside 15 minutes.

Salah then took centre stage to take his tally for the season to 15 goals in 12 appearances and become the top-scoring African player in Premier League history in the process.

To round off a miserable day for United, Paul Pogba lasted less than 15 minutes as a second-half substitute as he was shown a straight red card for a reckless lunge that forced Keita to leave the pitch on a stretcher.

Liverpool's first victory in front of a crowd at Old Trafford under Jurgen Klopp moves them back above Manchester City into second, just a point behind leaders Chelsea.

By contrast, United's hopes of a first league title since 2013 already look over as they remain eight points off the leaders.

That gap is likely to grow in the coming weeks with Tottenham and City to come in the next fortnight before an international break.

Whether Solskjaer will still be in charge come November is now in serious doubt as he has completely failed to form a balanced team from a talented collection of star players.

The Norwegian will wonder what might have been had Bruno Fernandes not fired over a glorious chance to open the scoring on three minutes.

But soon the defensive cracks that have blighted United's season began to appear.

Salah teed up Keita to open the floodgates after just five minutes with a composed low finish past David de Gea.

United came from 2-0 down at the break to beat Atalanta 3-2 in the Champions League on Wednesday.

But former midfielder Paul Scholes' warning after that match that Liverpool would be 4-0 up in 45 minutes if handed the same space to attack into came to fruition.

Jota justified his selection ahead of Sadio Mane as he stretched to turn in Trent Alexander-Arnold's cross to double Liverpool's advantage.

"I think it is great to win 5-0 here, we knew before the game it would be tough if we did not play our game," Salah said.

"We knew they will come and try to give everything so we had to give 100 per cent. We just tried to play our football and play in between the lines to create more chances. We did that and were lucky to score.

"As long as the team keep winning I am happy and to give my best to the team to win. The first goal I gave to Naby Keita to score."

Salah is the first away player to score a treble at Old Trafford since Brazil legend Ronaldo in 2003.

Salah has now scored in 10 consecutive games and overtook Didier Drogba with his 105th Premier League goal when the Egyptian turned home Keita's cut-back with the United defence all at sea.

The 29-year-old has now scored in 10 successive games in all competitions, while Liverpool are unbeaten in their last 22 games in all competitions.

"We know what it takes to win the Premier League, we did it two years ago. A big win here but still only three points," Salah said.

"We try to win each game and try to win the title. We need to play to win everything. From our heads from pre-season, we need to win the Premier League and hopefully we go for that.

"After half-time we were talking in the dressing room to just keep going and score as many as we could."

Cristiano Ronaldo was lucky to avoid a red card as United's frustrations bubbled over in first-half stoppage time when he was booked for lashing out at Curtis Jones in a sign of what was to come as the home side lost their discipline.

Liverpool inflicted further punishment before the break when Salah smashed home his 14th goal in 12 games this season at De Gea's near post.

Salah then completed his hat-trick with another cool finish five minutes into the second-half after Jordan Henderson's pass dissected the United defence once more.

Ronaldo thought he had pulled a goal back only for a VAR review to catch him in an offside position.

Another VAR check saw the end of Pogba's brief cameo for a horrendous studs-up challenge on Keita that forced the Guinean off.

Solskjaer sacrificed Fernandes and Marcus Rashford to try and stop the bleeding as Old Trafford emptied during the final half hour.

De Gea ensured Liverpool failed to match their record margin of victory against United with an incredible save from Alexander-Arnold's drive.

However, that did not subdue the mood among the travelling fans as they mockingly chanted for Solskjaer to remain in his job.