Match ends, West Bromwich Albion 2, Peterborough United 2.
League One Peterborough twice came from behind to earn a home FA Cup replay against a lacklustre West Brom.
In a rare start, striker Saido Berahino put the Premier League side ahead with a brilliant long-range finish.
Shaquile Coulthirst levelled for what was the first of three late goals in a space of an incredible seven minutes.
Berahino put the Baggies ahead once again from an acute angle before Jon Taylor earned the underdogs a draw with a hooked finish 60 seconds later.
Terrible defending led to Taylor's equaliser and a below-par West Brom were booed off for failing to overcome a side two divisions below them at home.
Last game for Berahino?
Baggies manager Tony Pulis opted to start with the unsettled Berahino, who has again been linked with a move in the January transfer window.
In the build up to the match, the Welshman said Berahino - who threatened to strike earlier this season after the club rejected transfer bids - had "wasted three or four months" of his career.
The England-21 international has failed to make an impact this season, scoring just three league goals, with 10 of his 18 appearances coming as a substitute.
But while the 22-year-old's all-round performance against Peterborough could have been better, his two superb goals illustrated why he has reportedly attracted the interest of a number of Premier League clubs.
He collected Rickie Lambert's past in the first half to finish with ease inside the D, while his second-half strike was an instinctive finish.
Berahino celebrated his second by cupping his ears to the home fans and, with transfer deadline day on Monday, it remains to be seen whether that was his last appearance for the club.
"He's a good player and he can score," said Albion boss Tony Pulis. "The problem we've got is his fitness is not what it should be - but put him in front of goal and he'll score.
"Will those be his last goals for the club? We'll see. That's the chairman's decision."
Baggies in a slump
West Brom's recent form will be a worry for their fans. They failed to register a shot on target in a 0-0 draw against Aston Villa last week, and should have dominated against Peterborough.
The hosts, fielding a strong line-up, were comfortable in the first half, but their lack of intensity after the break gave the League One promotion hopefuls another bite at the ABAX Stadium next month.
James McClean had two chances in the first half to double his team's lead, but of the Baggies' 13 shots on goal only four were on target.
Craig Gardner shot high over the crossbar when he should have done better after the break, and from there on Posh began to make inroads.
What they said:
West Brom manager Tony Pulis: "It's going to be four games in the first two rounds of the FA Cup - it's a lot of games for us, but at least we're still in the draw.
"It was our demise, when you're leading twice to concede the goals we did was pretty poor."
Peterborough manager Graham Westley: "The lads showed some great composure and some great maturity. I watched them grow this afternoon and I am very pleased.
"I think over the 90 minutes, the young players will have gained a lot of experience and they showed that important ingredient, desire.
"The replay will be tough because they are well managed and are a good side. We will give it our everything, it is the FA Cup."
West Brom - seven points above the relegation zone - will host Swansea in the Premier League on Tuesday and defeat against the Welsh team could drag the Baggies into a relegation scrap. Meanwhile, Peterborough, three points adrift of the play-offs, must refocus on their league visit to Chesterfield on 6 February.
- 29SessegnonSubstituted forAnichebeat 67'minutes
- 14McCleanBooked at 67mins
- 17LambertSubstituted forRondónat 63'minutes
- 2SmithBooked at 83mins
- 12Almeida Santos
- 38WilsonSubstituted forSamuelsenat 45'minutes
- 16BeautymanSubstituted forTaylorat 45'minutes
- 10OztumerSubstituted forMaddisonat 61'minutes
- 24AngolBooked at 84mins
- 22Da Silva Lopes
- Kevin Friend
- Shots on Target
Second Half ends, West Bromwich Albion 2, Peterborough United 2.
Attempt missed. Marcus Maddison (Peterborough United) left footed shot from outside the box is just a bit too high from a direct free kick.
Foul by Sébastien Pocognoli (West Bromwich Albion).
Martin Samuelsen (Peterborough United) wins a free kick in the attacking half.
Attempt blocked. Salomón Rondón (West Bromwich Albion) right footed shot from the centre of the box is blocked.
Attempt missed. Claudio Yacob (West Bromwich Albion) right footed shot from the centre of the box is just a bit too high.
Corner, West Bromwich Albion. Conceded by Ricardo Santos.
Salomón Rondón (West Bromwich Albion) wins a free kick on the left wing.
Foul by Ricardo Santos (Peterborough United).
Attempt saved. Martin Samuelsen (Peterborough United) left footed shot from the left side of the box is saved in the centre of the goal.
Goal! West Bromwich Albion 2, Peterborough United 2. Jon Taylor (Peterborough United) right footed shot from the centre of the box to the bottom left corner. Assisted by Ricardo Santos.
Goal! West Bromwich Albion 2, Peterborough United 1. Saido Berahino (West Bromwich Albion) right footed shot from the centre of the box to the bottom right corner. Assisted by Craig Dawson.
Lee Angol (Peterborough United) is shown the yellow card for a bad foul.
Craig Dawson (West Bromwich Albion) wins a free kick in the defensive half.
Foul by Ricardo Santos (Peterborough United).
Michael Smith (Peterborough United) is shown the yellow card for a bad foul.
James McClean (West Bromwich Albion) wins a free kick in the defensive half.
Foul by Michael Smith (Peterborough United).
Attempt blocked. Saido Berahino (West Bromwich Albion) right footed shot from outside the box is blocked.