Dunfermline's substitute Jamie McCunnie, who had already headed a Prso header off the line, tried to knock the ball out of the ground following a corner kick.
Their striker Martyn Waghorn headed a Zelalem header just past the post moments later but St Johnstone, despite some huffing and puffing in the latter stages, saw the game out to go deservedly into next Monday's quarter-final draw.
"Sitting here in Providence RI, USA, and you must have heard me in Reading when Walcott goal went in!" says Paul Janaway. ET 7 min Morrison heads Shorey's header over the bar.
As the hosts rallied, Martin Olsson headed a Jerome header off the line and from the ensuing corner Fer bundled over Jedinak and referee Mike Dean pointed to the spot.
McCaffrey's penalty was well-taken and the Glens could have extended their lead but Aaron Stewart headed David Howland's header off the line and Niall Henderson was unable to convert another chance.
Peter Crouch scored for Stoke in the 59th minute after his header was headed back to him by Jermaine Pennant.
Except, no: City switched off from a Philip Billing header, Mounie headed on and Stankovic got ahead of Stones to force home.
Wimbledon's own chances came in extra time, none more glaring than the header Yakubu headed wide of the near post in the 119th minute from an unmarked position.
Enyeama made a good save to stop Di María's toe-poke in the 37th minute, and the Lille midfielder Rio Mavuba was the next to rescue his side as he headed Layvin Kurzawa's header off the line four minutes later.
Brunt, who had earlier put a free header wide, headed the hosts in front.
Jordan Moore-Taylor levelled with 14 minutes to go before David Wheeler prodded in from close range in injury time after Christian Ribeiro had headed Liam Sercombe's header against the bar.
