Leicester advanced to the Carabao Cup quarter-finals with a 4-2 win on penalties following a 2-2 draw with Brighton at the King Power Stadium.
Brighton substitute Enock Mwepu scored the second-half equaliser which sent the game to penalties but saw his spot-kick saved by Leicester goalkeeper Danny Ward in the shootout as the Foxes claimed their place in the last eight.
Neal Maupay, another substitute on a night when both Brendan Rodgers and Graham Potter made wholesale changes to their starting line-ups, also missed his spot-kick in the shootout, the Brighton striker hitting the crossbar while Leicester converted all four of their efforts.
Earlier, the hosts had taken the lead when Harvey Barnes pounced on a loose pass from Brighton goalkeeper Jason Steele before charging into the box and firing an emphatic finish into the corner.
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Brighton didn't carry much of a threat after that sixth-minute setback but equalised in the third minute of first-half stoppage time when Aaron Webster turned home Shane Duffy's header.
It appeared they were heading into the interval level but more sloppy play saw Leicester equalise barely a minute later as the otherwise impressive Jeremy Sarmiento under-hit a backpass, allowing Ademola Lookman to round Steele and slot home.
Brighton hauled themselves level again when Mwepu's first goal for the club, a looping header from Marc Cucurella's cross, put them in the ascendency heading into the closing stages, but they could not find a winner and the hosts held their nerve from the spot.
Leicester: Ward (7), Soyuncu (7), Vestergaard (6), Bertrand (6), Daley-Campbell (6), Choudhury (6), Dewsbury-Hall (5), Thomas (6), Lookman (7), Barnes (8), Daka (8).
Subs: Mendy (6), Maddison (6), Soumare (6), Pereira (6), Iheanacho (6).
Brighton: Steele (6), Duffy (7), Webster (7), Roberts (6), Veltman (6), Gross (7), Mac Allister (6), Burn (6), Sarmiento (6), Connolly (5), Locadia (5).
Subs: Mwepu (7), Dunk (6), Bissouma (6), Cucurella (7), Maupay (6).
Man of the match: Harvey Barnes.
How Foxes emerged victorious
The evening began with a minute's silence to mark the third anniversary of the helicopter crash which claimed the lives of Leicester owner Vichai Srivaddhanaprabha and four others.
The hosts were straight onto the attack and the opener arrived after Patson Daka chased down a long ball, prompting panic in the Brighton defence and allowing Barnes to beat Webster to Steele's loose pass before unleashing a powerful finish.
It was ruthless from the 23-year-old, who looked eager to impress having recently lost his place in Rodgers' first-choice starting line-up, and Leicester soon came close to doubling their lead.
- Leicester made 10 changes from their 2-1 win over Brentford, with Vontae Daley-Campbell making only his second senior appearance at right wing-back.
- Brighton made eight changes from their 4-1 win over Man City, with Jeremy Sarmiento handed a debut and Shane Duffy returning at the back.
Daka was heavily involved again, the summer signing from Red Bull Salzburg accelerating away from Duffy on Leicester's left before cleverly cutting the ball back to Kiernan Dewsbury-Hall, whose powerful effort was touched onto the bar by Steele.
Brighton didn't offer much by way of response but they sprang into life in stoppage time. Alexis Mac Allister's long-range effort forced an acrobatic save from Ward and the visitors were level moments later when Duffy's header fell kindly for Webster following a corner.
Brighton's travelling fans had only just stopped celebrating when another poor pass, this time from the 19-year-old Sarmiento, who was making his debut, invited Lookman to take advantage and put the home side back in front.
Like Barnes, Lookman finished the chance coolly, but Brighton started the second half strongest and had an early opportunity to pull themselves level when Aaron Connolly shot tamely at Ward having been played through on goal.
Both managers made changes during the second period but it was Brighton's substitutes who made the biggest impact, with Cucurella's cross guided into the far corner by a back-peddling Mwepu in the 71st minute.
Before that, Barnes had spurned an opportunity to extend Leicester's lead, his low effort from Daka's through-ball drawing a fine save from Steele.
With the game level in the closing stages, there were opportunities for both sides to win it. Duffy's sliding block prevented Daka from testing Steele on one occasion, while up at the other end of the pitch Maupay and Connolly both misdirected headers.
In the end, it was decided from the spot. Maddison, Barnes, Daka and Ricardo Pereira all found the net for the hosts, with Maupay and Mwepu's misses allowing Leicester to claim their place in the quarter-finals.
What the managers said...
Leicester manager Brendan Rodgers: "It was always going to be a tough game. We've always had that against Brighton. I'm delighted with the mentality of the team.
"We had a lot of players who haven't played so much getting game-time. We fatigued a bit in the second half but we showed enough quality to get the goals and enough composure at the end to take the penalties and go through."
Brighton boss Graham Potter: "Really pleased with the performance. I thought the first 20 minutes were Leicester's. The goal was not a great one to concede but I felt we slowly got back into the game. We finished the first half really well and scored a good goal, but then conceded another poor goal.
"Credit to the boys, though, they responded well again. I thought they were really good in the second half. We got the equaliser and could maybe have got another one but overall it was a really good performance from us."
When is the draw for the Carabao Cup quarter-finals?
The quarter-final draw will take place live on Soccer AM this Saturday from 10.30am
Hosts Fenners and Jimmy Bullard will be conducting the draw, which will be live on Sky Sports Main Event, Sky Sports Football, Soccer AM's YouTube channel and the EFL's Twitter account.
Carabao Cup 2021/22 schedule...
- Fourth round: October 27
- Quarter-finals: December 21 and 22
- Semi-finals: January 4/5 and 11/12
- Final: February 27
What's next for Leicester and Brighton?
Leicester resume their Premier League campaign at home to Arsenal in Saturday's early kick-off while Brighton are away to Liverpool on Saturday at 3pm.