Match ends, Liverpool 2, West Bromwich Albion 2.
Divock Origi's deflected 95th-minute strike rescued a point for Liverpool against a resolute West Brom.
The home side began well and took the lead when Jordan Henderson finished a superb and patient passing move.
But Simon Mignolet's error gifted a goal to Craig Dawson of Albion, who were furious when a delayed offside flag denied Jonas Olsson a goal.
Olsson looked to have headed West Brom to victory before substitute Origi's shot found the net deep in added time.
Such was the relief around Anfield at full-time that Reds manager Jurgen Klopp called his entire team together to conduct on-field celebrations in front of the Kop.
The point earned means Liverpool are ninth in the table, five points off the top four, while the two points lost leave West Brom 13th, six points above the bottom three.
Positives for Liverpool
Striker Origi joined Liverpool in July 2014 for £10m but spent his first season on loan at Lille and has started only two league games this campaign.
However, after scoring a hat-trick in this month's 6-1 demolition of Southampton in the Capital One Cup, he now has a first, memorable league goal for the Reds, coming in the fifth of eight minutes added for a serious leg injury to defender Dejan Lovren, resulting from a tackle with Craig Gardner.
It came at the end of a game the home side largely dominated, both in terms of possession and shots.
Klopp's side had 70% of the ball, 28 attempts at goal to the Baggies' four and produced the goal of the game - a superb opener that began with goalkeeper Mignolet, comprised 20 passes and ended with Henderson firing home first time from Adam Lallana's downward header.
West Brom show their resilience
That Liverpool were forced to chase the game is down to a significant error from their goalkeeper, their own wastefulness in front of goal and West Brom's resilience.
Mignolet would undermine his side's good work soon after Henderson's opener with an air-punch from a corner that allowed Dawson to finish from close range.
With Liverpool's confidence visibly dented, West Brom took advantage and went ahead through Olsson's glancing header from a Chris Brunt corner.
However, during the course of the game, the home side had enough chances to win.
Between them, Philippe Coutinho and Christian Benteke had 10 shots, with the former firing the best of them over from 15 yards, while Lallana was denied by Boaz Myhill after breaking through the Baggies defence.
Controversial end to the first half
While the second half ended in drama, the first concluded in controversy.
West Brom thought they would be heading into the break in front after Olsson had volleyed home a Craig Gardner free-kick from close range. Indeed, the Baggies players managed a good 30 seconds of celebration before they were cut short by an extremely belated flag for offside.
Replays had shown the ultimate decision to be the right one but Albion manager Tony Pulis and his players were irate at the mysterious and protracted manner in which it was reached.
Man of the match - Jonas Olsson
What the managers said
Liverpool manager Jurgen Klopp: "I'm satisfied now because it was the perfect finish to this game. The one point was the minimum that we deserved today.
"Two set plays cost us. We knew about their quality in these situations. It was difficult. We created chances, made a perfect goal then conceded those two.
"But at the end I can live with it. This could prove to be a very special moment for us in the season to strike back against such a team."
West Brom manager Tony Pulis: "We're disappointed. We showed great resilience and to get done with a deflected goal in the eighth minute of stoppage time is particularly disappointing for the players.
"I can't fault the players. To come to a place like this with their budget, players and standing, we shouldn't be in their league."
On Albion having a goal ruled out for a 2-1 lead before half-time: "What disappointed me is the linesman doesn't put his flag up. If he puts his flag up straight away it is offside. Why the referee goes over and talks to him I don't know."
Liverpool travel to Watford next Sunday for a 13:30 GMT kick-off in the Premier League, while West Brom's final fixture before Christmas is at home against in-form Bournemouth on Saturday.
- 6LovrenSubstituted forOrigiat 79'minutes
- 20LallanaSubstituted forFirminoat 86'minutes
- 10CoutinhoSubstituted forIbeat 72'minutes
- 4K Touré
- 33RondónSubstituted forLambertat 90+4'minutes
- Craig Pawson
- Shots on Target
Second Half ends, Liverpool 2, West Bromwich Albion 2.
Attempt blocked. Nathaniel Clyne (Liverpool) right footed shot from outside the box is blocked. Assisted by Emre Can.
Goal! Liverpool 2, West Bromwich Albion 2. Divock Origi (Liverpool) right footed shot from outside the box to the bottom right corner. Assisted by Jordan Henderson.
Corner, Liverpool. Conceded by James Morrison.
Substitution, West Bromwich Albion. Rickie Lambert replaces Salomón Rondón.
Corner, Liverpool. Conceded by Craig Dawson.
Attempt blocked. Divock Origi (Liverpool) right footed shot from the left side of the box is blocked. Assisted by Christian Benteke.
Simon Mignolet (Liverpool) wins a free kick in the defensive half.
Foul by Salomón Rondón (West Bromwich Albion).
Foul by Christian Benteke (Liverpool).
Jonas Olsson (West Bromwich Albion) wins a free kick in the defensive half.
Attempt missed. Jordon Ibe (Liverpool) left footed shot from outside the box is close, but misses to the right. Assisted by Alberto Moreno.
Attempt saved. Jordan Henderson (Liverpool) right footed shot from outside the box is saved in the top centre of the goal. Assisted by Jordon Ibe.
Attempt missed. Salomón Rondón (West Bromwich Albion) right footed shot from outside the box is close, but misses to the left. Assisted by James McClean.
Attempt blocked. James Milner (Liverpool) right footed shot from outside the box is blocked. Assisted by Alberto Moreno.
Substitution, Liverpool. Roberto Firmino replaces Adam Lallana.
Hand ball by Craig Gardner (West Bromwich Albion).
Attempt blocked. James Milner (Liverpool) right footed shot from outside the box is blocked.
Attempt blocked. Alberto Moreno (Liverpool) left footed shot from outside the box is blocked.