Premier League side West Brom crashed out in the second round of the EFL Cup after losing to hosts Northampton in a penalty shootout at the Sixfields Stadium.
Last season's League Two champions who took the lead after defender Zander Diamond powered home a header from a corner before a goalkeeping gaffe from Adam Smith led to James McClean equalising for the Baggies.
West Brom took an early lead after the interval when defender Gareth McAuley headed in from a set piece only for veteran Cobblers striker Alex Revell to force extra-time with a close range finish in the dying minutes.