Deep into added time at the Hawthorns, with desperation gripping like wet rope, Alisson brilliantly headed home to maintain Liverpool’s pursuit of Champions League qualification.

Alisson became the first goalkeeper in Liverpool’s long and illustrious history to score after powering Trent Alexander-Arnold’s corner past Sam Johnstone to spark scenes of wild celebration on the bench. The Brazilian was mobbed 90 seconds later by jubilant team-mates after the final whistle, and rewarded with a huge bear-hug by manager Jurgen Klopp, after a remarkable finish.

What an emotional, magical moment it will have been for Alisson, who lost his father three months ago and revealed after the match that he wished he had been here to witness it.

For 90-odd minutes it had appeared that Klopp would again be haunted by the image of Sam Allardyce who continues to prove a serial irritant and was threatening to extend his unbeaten record against Klopp to six Premier League matches, leaving Liverpool’s top-four aspirations in the balance.

“Big Sam” was the first manager to stop Liverpool winning at Anfield this season, in December, and here was another challenging afternoon for Klopp. But just when it appeared that Allardyce would sentence them to a potentially damaging result, deep in stoppage time Alisson ventured forward to claim the three points and keep up the heat on Chelsea and Leicester.

Allardyce said: “Jurgen’s got away with one here, and he knows it. He’s a lucky man. Both the quality of the cross and the header [by Alisson] were brilliant. If we had someone marking him it might have been better but it’s not to be. It’s bitterly disappointing. We have been killed by a last-minute goal which is our fault but also what’s happened prior to that.”

Allardyce’s fury centred around a disallowed goal in the second-half after a VAR review, with Kyle Bartley’s finish ruled out as Matt Phillips was judged to have blocked Alisson’s vision. It appeared a harsh call, and prevented Albion from taking the lead for a second time.

For long periods they had been typically resolute and organised and if Allardyce is to leave West Brom this summer, his record against Klopp remains a huge source of personal pride. West Brom have already been relegated to the Championship but Klopp must have known this was going to be far from easy.

In a desperately tense encounter, Liverpool fell behind early on after displaying the defensive vulnerability that has plagued their season. Matheus Pereira’s clever flick breached the Liverpool back line and Hal Robson-Kanu advanced into the area before directing a fine shot across Alisson. Robson-Kanu was making his first appearance at this level since December 2017 and it was a brilliantly taken goal.

Liverpool dominated possession from that point but often lacked the killer instinct, with Sadio Mane shooting wide from six yards after a patient forward move.

Klopp revealed before kick-off that Mane had apologised for his refusal to shake his hand after Thursday’s victory at Manchester United.

Liverpool finally drew level in the 33rd minute through Mo Salah, whose composed, crisp finish from inside the area caught out Johnstone, after the ball had taken a deflection off Kyle Bartley. Salah has now scored 13 of his 22 league goals this season away from home.

Roberto Firmino, Liverpool’s captain, struck an upright after further defensive hesitation from West Brom and the visitors were in the ascendancy.

Mane had the ball in the net four minutes into the second half, but was flagged offside, while Salah was denied by Johnstone after a Liverpool breakaway.

Frustration was beginning to creep in with both managers. Klopp appeared irritable all afternoon while Allardyce was turning the air blue in his technical area. “You know what we f****** do, f****** stick to it!” was one particular instruction.

Desperation was also gripping Liverpool as time began to tick away. They escaped a second Albion goal 19 minutes from the end after a VAR check, with Phillips judged to have blocked Alisson’s vision when Bartley poked in from close range.

Alexander-Arnold lifted a shot over the bar six minutes from time and Johnstone dived to his right to save from Thiago Alcantara.

Four minutes of added time cranked up the tension, and the image of Alisson running up into the Albion area will now go down in Liverpool history.

Allardyce will make a decision on his future before the final game of the season at Leeds on Sunday.

“I wouldn’t answer the question about my position, even if I knew,” he said. “I’m just so dejected by this result. I don’t believe it.”

He was not the only one, after a day that will be forever etched into the minds of those who were present.

Telegraph Media Group Limited [2021]