West Bromwich Albion edge Peterborough after pens

West Brom survived an almighty scare against League One opponents Peterborough in the Emirates FA Cup before goalkeeper Ben Foster proved the shootout hero to set up a fifth round meeting with Reading.

The England international saved first from Martin Samuelsen before crucially Lee Angel on the final penalty to secure a 4-3 triumph and bring an end to Peterborough’s hopes of reaching the fifth round for the first time in 30 years.

Jon Taylor had earlier raised Peterborough hopes of a Cup upset when he fired the hosts deservedly in front on 55 minutes but Darren Fletcher thundered in an equaliser to force extra-time.

With the visitors having won just twice in their last 12 league games, a Cup upset was always a distinct possibility pre-match.

And the Posh started off the better side with Shaq Coulthirst shooting straight at Foster, Taylor firing wide and Michael Bostwick also drawing a save from Foster.

The visitors finally got their first shot on goal with Saido Berahino’s first-time volley going wide, while Harry Beautyman’s last ditch block denied James McClean.

But Peterborough got their breakthrough on 55 minutes when Taylor – scorer of his side’s dramatic equaliser in the first meeting – picked up the ball on the edge of the box before driving forward and shooting past Foster.

West Brom threatened on 70 minutes through an unmarked Craig Gardner. And just a minute later Fletcher dragged his side level as he connected with a McClean cross.

West Brom could have taken the lead in the last five minutes after Alnwick failed to clear a long ball, but Michael Bostwick was back to clear from Berahino.

Fletcher nearly repeated his first goal in the fifth minute of extra-time but his shot was blocked.

Samuelsen then had a fantastic chance to give Posh the lead after a dazzling run past five West Brom players but saw his driven shot sailed just over.

Both sides seemed determined not to head into penalties and, after Posh sub Marcus Maddison almost pulled off an audacious chip from 20 yards, the visitors thought they had won it in second-half stoppage time through Gardner but Gabriel Zakuani scooped off the line before an unmarked Berahino headed wide from a late freekick.

Both teams were successful with their first two penalties with Sebastien Pocognoli and Berahino scoring for West Brom and Bostwick and Maddison doing likewise for the hosts.

Samuelsen then saw his effort saved by Foster but Fletcher was unable to put his side 4-2 up as he screwed the ball horribly wide and Andrew Fox bought things level at 3-3 despite the efforts of Foster.

James Chester then put West Brom 4-3 up and when Angel could only shoot tamely at Foster, the celebrations became for the visitors.

Peterborough United (4-1-2-1-2): Ben Alnwick, Jack Baldwin, Gabriel Zakuani, Michael Bostwick Andrew Fox, Chris Forrester, Harry Beautyman, Jon Taylor, Martin Samuelsen, Shaquile Coulthirst, Lee Angol

Substitutes: Souleymane Coulibaly for Shaq Coulthirst 88, Marcus Maddison for Harry Beautyman 98, Erhun Oztumer for Jon Taylor 105.

Substitutes not used: Dion-Curtis Henry, Kgosi Ntlhe, Leonardo Da Silva Lopes, Harry Toffolo.

Goals: Jon Taylor 55.

Penalties: Michael Bostwick SCORED, Marcus Maddison SCORED, Martin Samuelsen SAVED, Andrew Fox SCORED, Lee Angol SAVED

West Bromwich Albion (4-4-2): Ben Foster, Gareth McAuley, Jonas Olsson, James Chester, Gary Gardner, Christian Gamboa, Darren Fletcher, Claudio Yacob, James McClean, Saido Berahino, Salomon Rondon.

Substitutes: Gareth McAuley for Sebastien Pocognoli 18, Stephane Sessegnon for Claudio Yacob 61.

Substitutes not used: Boaz Myhill, Victor Anichebe, Joe Ward, Tyler Roberts, Jonathan Leko

Goals: Darren Fletcher 71

Penalties: Sebastien Pocognoli SCORED, Saido Berahino SCORED, Craig Gardner, SCORED, Darren Fletcher WIDE, James Chester SCORED.

Attendance: 10,362

Referee: Michael Jones