David Nugent fired Leicester City through to the quarter-finals of the FA Cup with a superbly-taken winner against Norwich City at Carrow Road.
The visitors led through Sean St Ledger's header, but Wes Hoolahan levelled, following up his own penalty after Kasper Schmeichel had saved.
Both sides had efforts cleared off the line in pursuit of a winner.
But Nugent won it, collecting Jermaine Beckford's knockdown, before jinking through the Canaries defence to finish.
FA Cup Analysis
"Leicester were very measured in their approach and deserve a great deal of credit. Paul Lambert will be disappointed but at least Norwich can turn their full attention to doing well in the Premier League"
Nigel Worthington, former Norwich City manager on BBC Radio 5 live
Nigel Pearson had demanded a response from his Leicester side following their 3-2 midweek loss at Watford and got what he desired early on.
The Foxes pelted the Norwich penalty box with a series of corners and their fourth in quick succession, from Ben Marshall, found St Ledger, who rose above Steve Morison at the near post to glance home.
The early pace refused to ease and Leicester showed no signs of settling for a one-goal lead, pouring forward at every opportunity and looking like they had the Canaries rattled.
But Norwich were handed a respite when Foxes keeper Schmeichel conceded a penalty.
The Dane jumped over the top of Elliott Bennett and, although he got a fist to the ball, referee Mike Dean pointed to the spot.
Schmeichel saved Hoolahan's penalty kick superbly, diving to his left, but the ball spun back out to the Irishman who duly clattered it into an empty net.
Leicester, who already felt they were hard done by with the penalty decision, were doubly aggrieved moments later.
Teenage Canaries keeper Jed Steer could only flap at another dangerous Marshall corner and Wes Morgan's cleverly improvised back-heel effort was blocked on the line by Elliott Ward's chest.
The Foxes were adamant that the ball had crossed the line, but replays proved inconclusive.
Leicester were on the back foot themselves after the break when Richie Wellens twice denied Leon Barnett, clearing one effort from under his own bar and then directing a goal-bound header around the post.
DID YOU KNOW?
Leicester have beaten Norwich in their last five FA Cup meetings
Visiting left-back Paul Konchesky was also forced to scramble the ball away when Russell Martin put his header on target.
But fellow former England international Nugent showed a match-winning touch of class when he won the contest 19 minutes from time.
Collecting the ball in the Norwich half, he evaded a challenge from Barnett and skipped into the area before applying a cool finish for his third goal in two games - and his 13th of the campaign.
Norwich threw everything forward, bringing James Vaughan off the bench for his first appearance since a knee injury ruled him out in September.
But the best chance of the latter stages fell to Beckford, who crashed a left-footed effort against the post.
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