Sub Dyer nicks it as Leicester and Fulham share seven goals in thriller
Leicester substitute Lloyd Dyer scored the 89th-minute winner in a thrilling topsy-turvy 4-3 victory tie to book a place in the quarter-finals at Fulham's expense.
The promotion-chasing Foxes showed they were more than a match for Premier League opposition, although considering the Cottagers' struggles in the top flight it was difficult to describe the result as a shock.
Just eight league places separate the two sides with Leicester second in the Championship and they showed the character to bounce back from an 85th-minute equaliser – having led 3-1 – to snatch a 4-3 victory.
Hugo Rodallega's second goal of the season two months after his first, also in this competition, had put the visitors ahead only for the home side strike twice late on in the first half.
Fulham contributed significantly to their own downfall as individual errors led to both goals.
First goalkeeper Maarten Stekelenburg's fumbled long-range free-kick presented captain Wes Morgan with a simple close-range tap-in.
Less than five minutes later Philippe Senderos, who was the only outfield survivor from Saturday's 2-0 defeat at Southampton, hacked a clearance into Paul Konchesky and Chris Wood gratefully accepted the rebound.
Leicester made it three goals in 12 minutes either side of half-time when Ignasi Miquel headed in only for Rodallega to go straight down the other end and pull one back.
When Giorgos Karagounis smashed home a free-kick with five minutes remaining Leicester should have been crushed but they picked themselves up and Dyer delivered the knockout blow.
Elsewhere, A pair of second-half penalties from Matt Taylor and Jack Collison sent West Ham into the final eight as they ended 10-man Burnley's run of eight successive victories.
This was always likely to be a tricky tie for the Hammers with their opponents, leading the Championship, in such buoyant mood after recent results and bidding to win an 11th straight League Cup tie at Turf Moor.
Yet, in a much-improved second-half showing, Sam Allardyce's substitutions helped turn the tide in the visitors' favour with Kevin Nolan, one of those replacements, winning the all-important first spot-kick and Collison earning and converting the second.
As the visitors tried to force extra-time, Collison sprung on the break and was hauled down by Keith Treacy, with the winger being sent off, before the Welsh midfielder himself stroked home the penalty to hand Sean Dyche's men their first defeat since August.
Stoke progressed into the quarter-finals of the Capital One Cup as they saw off brave 10-man Birmingham on penalties following an incredible 4-4 thriller at St Andrew's.