West Brom needed penalties to defeat League One side Peterborough in an FA Cup fourth-round replay.
With the Premier League team leading 4-3 in the shootout, Posh striker Lee Angol had his spot-kick saved by Ben Foster to take the Baggies through.
Earlier, Jon Taylor – who scored the equaliser at The Hawthorns to take the tie to a replay – put Posh ahead.
But Darren Fletcher smashed in an equaliser for the visitors, who will play Reading in the fifth round.
Like Angol, Peterborough midfielder Martin Samuelsen also had a spot-kick saved in the shootout, but his miss was cancelled out when Fletcher slid his penalty wide.
Relive West Brom’s win over Peterborough
On the balance of play, Posh may feel aggrieved not to have won.
Led by a superb man-of-the-match display by West Ham loanee Samuelsen, Posh looked equal to a side 36 places above them in the football pyramid.
And the team eighth in League One almost opened the scoring when Harry Beautyman’s effort was blocked by a diving James Chester.
Beautyman had another chance in the first half, but allowed the ball to run across him instead of taking an instinctive shot in the area, which allowed Foster to get across to save.
Posh got their reward when Taylor latched on to a ball by Angol, ran into the area and shot across Foster to put Graham Westley’s side ahead.
West Brom came into the match having won just one of their past eight away matches, and without a Premier League win in five.
Manager Tony Pulis was dealt an early setback when defender Gareth McAuley had to come off injured.
But after a sustained spell of pressure from Posh, the Baggies, without a shot on target in three of their past four league games, finally found their feet late in the first half.
However, defender Chester somehow missed the target from a few yards out following a corner.
After another lull early in the second half, going behind gave them a second wind, and Fletcher scored his first FA Cup goal in eight years when he smashed home after James McClean’s cross was only partially cleared.
Posh defence stop onslaught
A West Brom win seemed inevitable after the equaliser, and Pulis’ side had the better of the extra 30 minutes.
But Michael Bostwick and Gabriel Zakuani, making his first start since 7 November because of injury, were equal to everything and blocked numerous attempts on goal. Zakuani’s goalline clearance from Craig Gardner’s half-volley was perhaps the pick of their efforts.
Saido Berahino should have won it for Albion in the final seconds but, when free at the back post, he headed Gardner’s free-kick wide before penalties settled the tie.
Man of the match – Martin Samuelsen
Peterborough boss Graham Westley: “Our lads will gain so much from that experience. They performed tremendously but now we have the league to concentrate on, as any manager would say.
“I never think it’s a big deal with a missed penalty. Anybody can miss a penalty. Both Martin Samuelsen and Lee Angol showed courage to go up there and will learn from the penalties they took.”
West Brom manager Tony Pulis: “That’s what the FA Cup is all about – the smaller team pushing the bigger team to the limit. Credit to them and British football. It is nerve-wracking but Peterborough should take a lot of credit.
“We want to do well in FA Cup but it has certainly affected us with injuries and pressure on the players. I want to do well in the cup as I have tremendous respect for it.”
The stats you need to know
- This was West Brom’s fourth shootout in the past three seasons (W3 D1). Only Carlisle have been involved in more during that time.
- West Brom have reached the FA Cup fifth round in successive seasons for the first time since 2008.
- Darren Fletcher scored his first FA Cup goal since two for Manchester United against Arsenal in February 2008.
- Peterborough have won none of their past 24 FA Cup games against a top-tier side (D7 L17).
West Brom have a trip to Everton for a 15:00 GMT kick-off on Saturday, while Peterborough host Bradford in League One on the same day.